Finite Math Examples

Find the Roots/Zeros Using the Rational Roots Test 4x^3-14x^2+25
4x3-14x2+25
Step 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,±5,±25
q=±1,±2,±4
Step 2
Find every combination of ±pq. These are the possible roots of the polynomial function.
±1,±12,±14,±5,±52,±54,±25,±252,±254
Step 3
Substitute the possible roots one by one into the polynomial to find the actual roots. Simplify to check if the value is 0, which means it is a root.
4(52)3-14(52)2+25
Step 4
Simplify the expression. In this case, the expression is equal to 0 so x=52 is a root of the polynomial.
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Step 4.1
Simplify each term.
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Step 4.1.1
Apply the product rule to 52.
45323-14(52)2+25
Step 4.1.2
Raise 5 to the power of 3.
412523-14(52)2+25
Step 4.1.3
Raise 2 to the power of 3.
4(1258)-14(52)2+25
Step 4.1.4
Cancel the common factor of 4.
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Step 4.1.4.1
Factor 4 out of 8.
41254(2)-14(52)2+25
Step 4.1.4.2
Cancel the common factor.
412542-14(52)2+25
Step 4.1.4.3
Rewrite the expression.
1252-14(52)2+25
1252-14(52)2+25
Step 4.1.5
Apply the product rule to 52.
1252-145222+25
Step 4.1.6
Raise 5 to the power of 2.
1252-142522+25
Step 4.1.7
Raise 2 to the power of 2.
1252-14(254)+25
Step 4.1.8
Cancel the common factor of 2.
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Step 4.1.8.1
Factor 2 out of -14.
1252+2(-7)254+25
Step 4.1.8.2
Factor 2 out of 4.
1252+2-72522+25
Step 4.1.8.3
Cancel the common factor.
1252+2-72522+25
Step 4.1.8.4
Rewrite the expression.
1252-7(252)+25
1252-7(252)+25
Step 4.1.9
Combine -7 and 252.
1252+-7252+25
Step 4.1.10
Multiply -7 by 25.
1252+-1752+25
Step 4.1.11
Move the negative in front of the fraction.
1252-1752+25
1252-1752+25
Step 4.2
Combine fractions.
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Step 4.2.1
Combine the numerators over the common denominator.
25+125-1752
Step 4.2.2
Simplify the expression.
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Step 4.2.2.1
Subtract 175 from 125.
25+-502
Step 4.2.2.2
Divide -50 by 2.
25-25
Step 4.2.2.3
Subtract 25 from 25.
0
0
0
0
Step 5
Since 52 is a known root, divide the polynomial by x-52 to find the quotient polynomial. This polynomial can then be used to find the remaining roots.
4x3-14x2+25x-52
Step 6
Next, find the roots of the remaining polynomial. The order of the polynomial has been reduced by 1.
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Step 6.1
Place the numbers representing the divisor and the dividend into a division-like configuration.
524-14025
  
Step 6.2
The first number in the dividend (4) is put into the first position of the result area (below the horizontal line).
524-14025
  
4
Step 6.3
Multiply the newest entry in the result (4) by the divisor (52) and place the result of (10) under the next term in the dividend (-14).
524-14025
 10 
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.
524-14025
 10 
4-4
Step 6.5
Multiply the newest entry in the result (-4) by the divisor (52) and place the result of (-10) under the next term in the dividend (0).
524-14025
 10-10 
4-4
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.
524-14025
 10-10 
4-4-10
Step 6.7
Multiply the newest entry in the result (-10) by the divisor (52) and place the result of (-25) under the next term in the dividend (25).
524-14025
 10-10-25
4-4-10
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.
524-14025
 10-10-25
4-4-100
Step 6.9
All numbers except the last become the coefficients of the quotient polynomial. The last value in the result line is the remainder.
4x2+-4x-10
Step 6.10
Simplify the quotient polynomial.
4x2-4x-10
4x2-4x-10
Step 7
Factor 2 out of 4x2-4x-10.
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Step 7.1
Factor 2 out of 4x2.
(x-52)(2(2x2)-4x-10)
Step 7.2
Factor 2 out of -4x.
(x-52)(2(2x2)+2(-2x)-10)
Step 7.3
Factor 2 out of -10.
(x-52)(2(2x2)+2(-2x)+2(-5))
Step 7.4
Factor 2 out of 2(2x2)+2(-2x).
(x-52)(2(2x2-2x)+2(-5))
Step 7.5
Factor 2 out of 2(2x2-2x)+2(-5).
(x-52)(2(2x2-2x-5))
(x-52)(2(2x2-2x-5))
Step 8
Factor 4x3-14x2+25 using the rational roots test.
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Step 8.1
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,±25,±5
q=±1,±4,±2
Step 8.2
Find every combination of ±pq. These are the possible roots of the polynomial function.
±1,±0.25,±0.5,±25,±6.25,±12.5,±5,±1.25,±2.5
Step 8.3
Substitute 2.5 and simplify the expression. In this case, the expression is equal to 0 so 2.5 is a root of the polynomial.
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Step 8.3.1
Substitute 2.5 into the polynomial.
42.53-142.52+25
Step 8.3.2
Raise 2.5 to the power of 3.
415.625-142.52+25
Step 8.3.3
Multiply 4 by 15.625.
62.5-142.52+25
Step 8.3.4
Raise 2.5 to the power of 2.
62.5-146.25+25
Step 8.3.5
Multiply -14 by 6.25.
62.5-87.5+25
Step 8.3.6
Subtract 87.5 from 62.5.
-25+25
Step 8.3.7
Add -25 and 25.
0
0
Step 8.4
Since 2.5 is a known root, divide the polynomial by 2x-5 to find the quotient polynomial. This polynomial can then be used to find the remaining roots.
4x3-14x2+252x-5
Step 8.5
Divide 4x3-14x2+25 by 2x-5.
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Step 8.5.1
Set up the polynomials to be divided. If there is not a term for every exponent, insert one with a value of 0.
2x-54x3-14x2+0x+25
Step 8.5.2
Divide the highest order term in the dividend 4x3 by the highest order term in divisor 2x.
2x2
2x-54x3-14x2+0x+25
Step 8.5.3
Multiply the new quotient term by the divisor.
2x2
2x-54x3-14x2+0x+25
+4x3-10x2
Step 8.5.4
The expression needs to be subtracted from the dividend, so change all the signs in 4x3-10x2
2x2
2x-54x3-14x2+0x+25
-4x3+10x2
Step 8.5.5
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
2x2
2x-54x3-14x2+0x+25
-4x3+10x2
-4x2
Step 8.5.6
Pull the next terms from the original dividend down into the current dividend.
2x2
2x-54x3-14x2+0x+25
-4x3+10x2
-4x2+0x
Step 8.5.7
Divide the highest order term in the dividend -4x2 by the highest order term in divisor 2x.
2x2-2x
2x-54x3-14x2+0x+25
-4x3+10x2
-4x2+0x
Step 8.5.8
Multiply the new quotient term by the divisor.
2x2-2x
2x-54x3-14x2+0x+25
-4x3+10x2
-4x2+0x
-4x2+10x
Step 8.5.9
The expression needs to be subtracted from the dividend, so change all the signs in -4x2+10x
2x2-2x
2x-54x3-14x2+0x+25
-4x3+10x2
-4x2+0x
+4x2-10x
Step 8.5.10
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
2x2-2x
2x-54x3-14x2+0x+25
-4x3+10x2
-4x2+0x
+4x2-10x
-10x
Step 8.5.11
Pull the next terms from the original dividend down into the current dividend.
2x2-2x
2x-54x3-14x2+0x+25
-4x3+10x2
-4x2+0x
+4x2-10x
-10x+25
Step 8.5.12
Divide the highest order term in the dividend -10x by the highest order term in divisor 2x.
2x2-2x-5
2x-54x3-14x2+0x+25
-4x3+10x2
-4x2+0x
+4x2-10x
-10x+25
Step 8.5.13
Multiply the new quotient term by the divisor.
2x2-2x-5
2x-54x3-14x2+0x+25
-4x3+10x2
-4x2+0x
+4x2-10x
-10x+25
-10x+25
Step 8.5.14
The expression needs to be subtracted from the dividend, so change all the signs in -10x+25
2x2-2x-5
2x-54x3-14x2+0x+25
-4x3+10x2
-4x2+0x
+4x2-10x
-10x+25
+10x-25
Step 8.5.15
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
2x2-2x-5
2x-54x3-14x2+0x+25
-4x3+10x2
-4x2+0x
+4x2-10x
-10x+25
+10x-25
0
Step 8.5.16
Since the remander is 0, the final answer is the quotient.
2x2-2x-5
2x2-2x-5
Step 8.6
Write 4x3-14x2+25 as a set of factors.
(2x-5)(2x2-2x-5)=0
(2x-5)(2x2-2x-5)=0
Step 9
If any individual factor on the left side of the equation is equal to 0, the entire expression will be equal to 0.
2x-5=0
2x2-2x-5=0
Step 10
Set 2x-5 equal to 0 and solve for x.
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Step 10.1
Set 2x-5 equal to 0.
2x-5=0
Step 10.2
Solve 2x-5=0 for x.
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Step 10.2.1
Add 5 to both sides of the equation.
2x=5
Step 10.2.2
Divide each term in 2x=5 by 2 and simplify.
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Step 10.2.2.1
Divide each term in 2x=5 by 2.
2x2=52
Step 10.2.2.2
Simplify the left side.
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Step 10.2.2.2.1
Cancel the common factor of 2.
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Step 10.2.2.2.1.1
Cancel the common factor.
2x2=52
Step 10.2.2.2.1.2
Divide x by 1.
x=52
x=52
x=52
x=52
x=52
x=52
Step 11
Set 2x2-2x-5 equal to 0 and solve for x.
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Step 11.1
Set 2x2-2x-5 equal to 0.
2x2-2x-5=0
Step 11.2
Solve 2x2-2x-5=0 for x.
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Step 11.2.1
Use the quadratic formula to find the solutions.
-b±b2-4(ac)2a
Step 11.2.2
Substitute the values a=2, b=-2, and c=-5 into the quadratic formula and solve for x.
2±(-2)2-4(2-5)22
Step 11.2.3
Simplify.
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Step 11.2.3.1
Simplify the numerator.
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Step 11.2.3.1.1
Raise -2 to the power of 2.
x=2±4-42-522
Step 11.2.3.1.2
Multiply -42-5.
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Step 11.2.3.1.2.1
Multiply -4 by 2.
x=2±4-8-522
Step 11.2.3.1.2.2
Multiply -8 by -5.
x=2±4+4022
x=2±4+4022
Step 11.2.3.1.3
Add 4 and 40.
x=2±4422
Step 11.2.3.1.4
Rewrite 44 as 2211.
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Step 11.2.3.1.4.1
Factor 4 out of 44.
x=2±4(11)22
Step 11.2.3.1.4.2
Rewrite 4 as 22.
x=2±221122
x=2±221122
Step 11.2.3.1.5
Pull terms out from under the radical.
x=2±21122
x=2±21122
Step 11.2.3.2
Multiply 2 by 2.
x=2±2114
Step 11.2.3.3
Simplify 2±2114.
x=1±112
x=1±112
Step 11.2.4
Simplify the expression to solve for the + portion of the ±.
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Step 11.2.4.1
Simplify the numerator.
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Step 11.2.4.1.1
Raise -2 to the power of 2.
x=2±4-42-522
Step 11.2.4.1.2
Multiply -42-5.
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Step 11.2.4.1.2.1
Multiply -4 by 2.
x=2±4-8-522
Step 11.2.4.1.2.2
Multiply -8 by -5.
x=2±4+4022
x=2±4+4022
Step 11.2.4.1.3
Add 4 and 40.
x=2±4422
Step 11.2.4.1.4
Rewrite 44 as 2211.
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Step 11.2.4.1.4.1
Factor 4 out of 44.
x=2±4(11)22
Step 11.2.4.1.4.2
Rewrite 4 as 22.
x=2±221122
x=2±221122
Step 11.2.4.1.5
Pull terms out from under the radical.
x=2±21122
x=2±21122
Step 11.2.4.2
Multiply 2 by 2.
x=2±2114
Step 11.2.4.3
Simplify 2±2114.
x=1±112
Step 11.2.4.4
Change the ± to +.
x=1+112
x=1+112
Step 11.2.5
Simplify the expression to solve for the - portion of the ±.
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Step 11.2.5.1
Simplify the numerator.
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Step 11.2.5.1.1
Raise -2 to the power of 2.
x=2±4-42-522
Step 11.2.5.1.2
Multiply -42-5.
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Step 11.2.5.1.2.1
Multiply -4 by 2.
x=2±4-8-522
Step 11.2.5.1.2.2
Multiply -8 by -5.
x=2±4+4022
x=2±4+4022
Step 11.2.5.1.3
Add 4 and 40.
x=2±4422
Step 11.2.5.1.4
Rewrite 44 as 2211.
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Step 11.2.5.1.4.1
Factor 4 out of 44.
x=2±4(11)22
Step 11.2.5.1.4.2
Rewrite 4 as 22.
x=2±221122
x=2±221122
Step 11.2.5.1.5
Pull terms out from under the radical.
x=2±21122
x=2±21122
Step 11.2.5.2
Multiply 2 by 2.
x=2±2114
Step 11.2.5.3
Simplify 2±2114.
x=1±112
Step 11.2.5.4
Change the ± to -.
x=1-112
x=1-112
Step 11.2.6
The final answer is the combination of both solutions.
x=1+112,1-112
x=1+112,1-112
x=1+112,1-112
Step 12
The final solution is all the values that make (2x-5)(2x2-2x-5)=0 true.
x=52,1+112,1-112
Step 13
The result can be shown in multiple forms.
Exact Form:
x=52,1+112,1-112
Decimal Form:
x=2.5,2.15831239,-1.15831239
Mixed Number Form:
x=212,1+112,1-112
Step 14
 [x2  12  π  xdx ]