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Precalculus Examples
p(x)=4x4+8x3-7x2-21x-9p(x)=4x4+8x3−7x2−21x−9
Step 1
Step 1.1
If a polynomial function has integer coefficients, then every rational zero will have the form pq where p is a factor of the constant and q is a factor of the leading coefficient.
p=±1,±3,±9
q=±1,±2,±4
Step 1.2
Find every combination of ±pq. These are the possible roots of the polynomial function.
±1,±12,±14,±3,±32,±34,±9,±92,±94
±1,±12,±14,±3,±32,±34,±9,±92,±94
Step 2
Step 2.1
Place the numbers representing the divisor and the dividend into a division-like configuration.
3 | 4 | 8 | -7 | -21 | -9 |
Step 2.2
The first number in the dividend (4) is put into the first position of the result area (below the horizontal line).
3 | 4 | 8 | -7 | -21 | -9 |
4 |
Step 2.3
Multiply the newest entry in the result (4) by the divisor (3) and place the result of (12) under the next term in the dividend (8).
3 | 4 | 8 | -7 | -21 | -9 |
12 | |||||
4 |
Step 2.4
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
3 | 4 | 8 | -7 | -21 | -9 |
12 | |||||
4 | 20 |
Step 2.5
Multiply the newest entry in the result (20) by the divisor (3) and place the result of (60) under the next term in the dividend (-7).
3 | 4 | 8 | -7 | -21 | -9 |
12 | 60 | ||||
4 | 20 |
Step 2.6
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
3 | 4 | 8 | -7 | -21 | -9 |
12 | 60 | ||||
4 | 20 | 53 |
Step 2.7
Multiply the newest entry in the result (53) by the divisor (3) and place the result of (159) under the next term in the dividend (-21).
3 | 4 | 8 | -7 | -21 | -9 |
12 | 60 | 159 | |||
4 | 20 | 53 |
Step 2.8
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
3 | 4 | 8 | -7 | -21 | -9 |
12 | 60 | 159 | |||
4 | 20 | 53 | 138 |
Step 2.9
Multiply the newest entry in the result (138) by the divisor (3) and place the result of (414) under the next term in the dividend (-9).
3 | 4 | 8 | -7 | -21 | -9 |
12 | 60 | 159 | 414 | ||
4 | 20 | 53 | 138 |
Step 2.10
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
3 | 4 | 8 | -7 | -21 | -9 |
12 | 60 | 159 | 414 | ||
4 | 20 | 53 | 138 | 405 |
Step 2.11
All numbers except the last become the coefficients of the quotient polynomial. The last value in the result line is the remainder.
4x3+20x2+(53)x+138+405x-3
Step 2.12
Simplify the quotient polynomial.
4x3+20x2+53x+138+405x-3
4x3+20x2+53x+138+405x-3
Step 3
Since 3>0 and all of the signs in the bottom row of the synthetic division are positive, 3 is an upper bound for the real roots of the function.
Upper Bound: 3
Step 4
Step 4.1
Place the numbers representing the divisor and the dividend into a division-like configuration.
-3 | 4 | 8 | -7 | -21 | -9 |
Step 4.2
The first number in the dividend (4) is put into the first position of the result area (below the horizontal line).
-3 | 4 | 8 | -7 | -21 | -9 |
4 |
Step 4.3
Multiply the newest entry in the result (4) by the divisor (-3) and place the result of (-12) under the next term in the dividend (8).
-3 | 4 | 8 | -7 | -21 | -9 |
-12 | |||||
4 |
Step 4.4
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
-3 | 4 | 8 | -7 | -21 | -9 |
-12 | |||||
4 | -4 |
Step 4.5
Multiply the newest entry in the result (-4) by the divisor (-3) and place the result of (12) under the next term in the dividend (-7).
-3 | 4 | 8 | -7 | -21 | -9 |
-12 | 12 | ||||
4 | -4 |
Step 4.6
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
-3 | 4 | 8 | -7 | -21 | -9 |
-12 | 12 | ||||
4 | -4 | 5 |
Step 4.7
Multiply the newest entry in the result (5) by the divisor (-3) and place the result of (-15) under the next term in the dividend (-21).
-3 | 4 | 8 | -7 | -21 | -9 |
-12 | 12 | -15 | |||
4 | -4 | 5 |
Step 4.8
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
-3 | 4 | 8 | -7 | -21 | -9 |
-12 | 12 | -15 | |||
4 | -4 | 5 | -36 |
Step 4.9
Multiply the newest entry in the result (-36) by the divisor (-3) and place the result of (108) under the next term in the dividend (-9).
-3 | 4 | 8 | -7 | -21 | -9 |
-12 | 12 | -15 | 108 | ||
4 | -4 | 5 | -36 |
Step 4.10
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
-3 | 4 | 8 | -7 | -21 | -9 |
-12 | 12 | -15 | 108 | ||
4 | -4 | 5 | -36 | 99 |
Step 4.11
All numbers except the last become the coefficients of the quotient polynomial. The last value in the result line is the remainder.
4x3+-4x2+(5)x-36+99x+3
Step 4.12
Simplify the quotient polynomial.
4x3-4x2+5x-36+99x+3
4x3-4x2+5x-36+99x+3
Step 5
Since -3<0 and the signs in the bottom row of the synthetic division alternate sign, -3 is a lower bound for the real roots of the function.
Lower Bound: -3
Step 6
Step 6.1
Place the numbers representing the divisor and the dividend into a division-like configuration.
9 | 4 | 8 | -7 | -21 | -9 |
Step 6.2
The first number in the dividend (4) is put into the first position of the result area (below the horizontal line).
9 | 4 | 8 | -7 | -21 | -9 |
4 |
Step 6.3
Multiply the newest entry in the result (4) by the divisor (9) and place the result of (36) under the next term in the dividend (8).
9 | 4 | 8 | -7 | -21 | -9 |
36 | |||||
4 |
Step 6.4
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
9 | 4 | 8 | -7 | -21 | -9 |
36 | |||||
4 | 44 |
Step 6.5
Multiply the newest entry in the result (44) by the divisor (9) and place the result of (396) under the next term in the dividend (-7).
9 | 4 | 8 | -7 | -21 | -9 |
36 | 396 | ||||
4 | 44 |
Step 6.6
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
9 | 4 | 8 | -7 | -21 | -9 |
36 | 396 | ||||
4 | 44 | 389 |
Step 6.7
Multiply the newest entry in the result (389) by the divisor (9) and place the result of (3501) under the next term in the dividend (-21).
9 | 4 | 8 | -7 | -21 | -9 |
36 | 396 | 3501 | |||
4 | 44 | 389 |
Step 6.8
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
9 | 4 | 8 | -7 | -21 | -9 |
36 | 396 | 3501 | |||
4 | 44 | 389 | 3480 |
Step 6.9
Multiply the newest entry in the result (3480) by the divisor (9) and place the result of (31320) under the next term in the dividend (-9).
9 | 4 | 8 | -7 | -21 | -9 |
36 | 396 | 3501 | 31320 | ||
4 | 44 | 389 | 3480 |
Step 6.10
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
9 | 4 | 8 | -7 | -21 | -9 |
36 | 396 | 3501 | 31320 | ||
4 | 44 | 389 | 3480 | 31311 |
Step 6.11
All numbers except the last become the coefficients of the quotient polynomial. The last value in the result line is the remainder.
4x3+44x2+(389)x+3480+31311x-9
Step 6.12
Simplify the quotient polynomial.
4x3+44x2+389x+3480+31311x-9
4x3+44x2+389x+3480+31311x-9
Step 7
Since 9>0 and all of the signs in the bottom row of the synthetic division are positive, 9 is an upper bound for the real roots of the function.
Upper Bound: 9
Step 8
Step 8.1
Place the numbers representing the divisor and the dividend into a division-like configuration.
-9 | 4 | 8 | -7 | -21 | -9 |
Step 8.2
The first number in the dividend (4) is put into the first position of the result area (below the horizontal line).
-9 | 4 | 8 | -7 | -21 | -9 |
4 |
Step 8.3
Multiply the newest entry in the result (4) by the divisor (-9) and place the result of (-36) under the next term in the dividend (8).
-9 | 4 | 8 | -7 | -21 | -9 |
-36 | |||||
4 |
Step 8.4
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
-9 | 4 | 8 | -7 | -21 | -9 |
-36 | |||||
4 | -28 |
Step 8.5
Multiply the newest entry in the result (-28) by the divisor (-9) and place the result of (252) under the next term in the dividend (-7).
-9 | 4 | 8 | -7 | -21 | -9 |
-36 | 252 | ||||
4 | -28 |
Step 8.6
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
-9 | 4 | 8 | -7 | -21 | -9 |
-36 | 252 | ||||
4 | -28 | 245 |
Step 8.7
Multiply the newest entry in the result (245) by the divisor (-9) and place the result of (-2205) under the next term in the dividend (-21).
-9 | 4 | 8 | -7 | -21 | -9 |
-36 | 252 | -2205 | |||
4 | -28 | 245 |
Step 8.8
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
-9 | 4 | 8 | -7 | -21 | -9 |
-36 | 252 | -2205 | |||
4 | -28 | 245 | -2226 |
Step 8.9
Multiply the newest entry in the result (-2226) by the divisor (-9) and place the result of (20034) under the next term in the dividend (-9).
-9 | 4 | 8 | -7 | -21 | -9 |
-36 | 252 | -2205 | 20034 | ||
4 | -28 | 245 | -2226 |
Step 8.10
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
-9 | 4 | 8 | -7 | -21 | -9 |
-36 | 252 | -2205 | 20034 | ||
4 | -28 | 245 | -2226 | 20025 |
Step 8.11
All numbers except the last become the coefficients of the quotient polynomial. The last value in the result line is the remainder.
4x3+-28x2+(245)x-2226+20025x+9
Step 8.12
Simplify the quotient polynomial.
4x3-28x2+245x-2226+20025x+9
4x3-28x2+245x-2226+20025x+9
Step 9
Since -9<0 and the signs in the bottom row of the synthetic division alternate sign, -9 is a lower bound for the real roots of the function.
Lower Bound: -9
Step 10
Step 10.1
Place the numbers representing the divisor and the dividend into a division-like configuration.
92 | 4 | 8 | -7 | -21 | -9 |
Step 10.2
The first number in the dividend (4) is put into the first position of the result area (below the horizontal line).
92 | 4 | 8 | -7 | -21 | -9 |
4 |
Step 10.3
Multiply the newest entry in the result (4) by the divisor (92) and place the result of (18) under the next term in the dividend (8).
92 | 4 | 8 | -7 | -21 | -9 |
18 | |||||
4 |
Step 10.4
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
92 | 4 | 8 | -7 | -21 | -9 |
18 | |||||
4 | 26 |
Step 10.5
Multiply the newest entry in the result (26) by the divisor (92) and place the result of (117) under the next term in the dividend (-7).
92 | 4 | 8 | -7 | -21 | -9 |
18 | 117 | ||||
4 | 26 |
Step 10.6
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
92 | 4 | 8 | -7 | -21 | -9 |
18 | 117 | ||||
4 | 26 | 110 |
Step 10.7
Multiply the newest entry in the result (110) by the divisor (92) and place the result of (495) under the next term in the dividend (-21).
92 | 4 | 8 | -7 | -21 | -9 |
18 | 117 | 495 | |||
4 | 26 | 110 |
Step 10.8
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
92 | 4 | 8 | -7 | -21 | -9 |
18 | 117 | 495 | |||
4 | 26 | 110 | 474 |
Step 10.9
Multiply the newest entry in the result (474) by the divisor (92) and place the result of (2133) under the next term in the dividend (-9).
92 | 4 | 8 | -7 | -21 | -9 |
18 | 117 | 495 | 2133 | ||
4 | 26 | 110 | 474 |
Step 10.10
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
92 | 4 | 8 | -7 | -21 | -9 |
18 | 117 | 495 | 2133 | ||
4 | 26 | 110 | 474 | 2124 |
Step 10.11
All numbers except the last become the coefficients of the quotient polynomial. The last value in the result line is the remainder.
4x3+26x2+(110)x+474+2124x-92
Step 10.12
Simplify the quotient polynomial.
4x3+26x2+110x+474+42482x-9
4x3+26x2+110x+474+42482x-9
Step 11
Since 92>0 and all of the signs in the bottom row of the synthetic division are positive, 92 is an upper bound for the real roots of the function.
Upper Bound: 92
Step 12
Step 12.1
Place the numbers representing the divisor and the dividend into a division-like configuration.
-92 | 4 | 8 | -7 | -21 | -9 |
Step 12.2
The first number in the dividend (4) is put into the first position of the result area (below the horizontal line).
-92 | 4 | 8 | -7 | -21 | -9 |
4 |
Step 12.3
Multiply the newest entry in the result (4) by the divisor (-92) and place the result of (-18) under the next term in the dividend (8).
-92 | 4 | 8 | -7 | -21 | -9 |
-18 | |||||
4 |
Step 12.4
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
-92 | 4 | 8 | -7 | -21 | -9 |
-18 | |||||
4 | -10 |
Step 12.5
Multiply the newest entry in the result (-10) by the divisor (-92) and place the result of (45) under the next term in the dividend (-7).
-92 | 4 | 8 | -7 | -21 | -9 |
-18 | 45 | ||||
4 | -10 |
Step 12.6
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
-92 | 4 | 8 | -7 | -21 | -9 |
-18 | 45 | ||||
4 | -10 | 38 |
Step 12.7
Multiply the newest entry in the result (38) by the divisor (-92) and place the result of (-171) under the next term in the dividend (-21).
-92 | 4 | 8 | -7 | -21 | -9 |
-18 | 45 | -171 | |||
4 | -10 | 38 |
Step 12.8
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
-92 | 4 | 8 | -7 | -21 | -9 |
-18 | 45 | -171 | |||
4 | -10 | 38 | -192 |
Step 12.9
Multiply the newest entry in the result (-192) by the divisor (-92) and place the result of (864) under the next term in the dividend (-9).
-92 | 4 | 8 | -7 | -21 | -9 |
-18 | 45 | -171 | 864 | ||
4 | -10 | 38 | -192 |
Step 12.10
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
-92 | 4 | 8 | -7 | -21 | -9 |
-18 | 45 | -171 | 864 | ||
4 | -10 | 38 | -192 | 855 |
Step 12.11
All numbers except the last become the coefficients of the quotient polynomial. The last value in the result line is the remainder.
4x3+-10x2+(38)x-192+855x+92
Step 12.12
Simplify the quotient polynomial.
4x3-10x2+38x-192+17102x+9
4x3-10x2+38x-192+17102x+9
Step 13
Since -92<0 and the signs in the bottom row of the synthetic division alternate sign, -92 is a lower bound for the real roots of the function.
Lower Bound: -92
Step 14
Step 14.1
Place the numbers representing the divisor and the dividend into a division-like configuration.
94 | 4 | 8 | -7 | -21 | -9 |
Step 14.2
The first number in the dividend (4) is put into the first position of the result area (below the horizontal line).
94 | 4 | 8 | -7 | -21 | -9 |
4 |
Step 14.3
Multiply the newest entry in the result (4) by the divisor (94) and place the result of (9) under the next term in the dividend (8).
94 | 4 | 8 | -7 | -21 | -9 |
9 | |||||
4 |
Step 14.4
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
94 | 4 | 8 | -7 | -21 | -9 |
9 | |||||
4 | 17 |
Step 14.5
Multiply the newest entry in the result (17) by the divisor (94) and place the result of (1534) under the next term in the dividend (-7).
94 | 4 | 8 | -7 | -21 | -9 |
9 | 1534 | ||||
4 | 17 |
Step 14.6
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
94 | 4 | 8 | -7 | -21 | -9 |
9 | 1534 | ||||
4 | 17 | 1254 |
Step 14.7
Multiply the newest entry in the result (1254) by the divisor (94) and place the result of (112516) under the next term in the dividend (-21).
94 | 4 | 8 | -7 | -21 | -9 |
9 | 1534 | 112516 | |||
4 | 17 | 1254 |
Step 14.8
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
94 | 4 | 8 | -7 | -21 | -9 |
9 | 1534 | 112516 | |||
4 | 17 | 1254 | 78916 |
Step 14.9
Multiply the newest entry in the result (78916) by the divisor (94) and place the result of (710164) under the next term in the dividend (-9).
94 | 4 | 8 | -7 | -21 | -9 |
9 | 1534 | 112516 | 710164 | ||
4 | 17 | 1254 | 78916 |
Step 14.10
Add the product of the multiplication and the number from the dividend and put the result in the next position on the result line.
94 | 4 | 8 | -7 | -21 | -9 |
9 | 1534 | 112516 | 710164 | ||
4 | 17 | 1254 | 78916 | 652564 |
Step 14.11
All numbers except the last become the coefficients of the quotient polynomial. The last value in the result line is the remainder.
4x3+17x2+(1254)x+78916+652564x-94
Step 14.12
Simplify the quotient polynomial.
4x3+17x2+125x4+78916+652516(4x-9)
4x3+17x2+125x4+78916+652516(4x-9)
Step 15
Since 94>0 and all of the signs in the bottom row of the synthetic division are positive, 94 is an upper bound for the real roots of the function.
Upper Bound: 94
Step 16
Determine the upper and lower bounds.
Upper Bounds: 3,9,92,94
Lower Bounds: -3,-9,-92
Step 17
