Examples
x2+4x+4x2+4x+4
Step 1
If a polynomial function has integer coefficients, then every rational zero will have the form pqpq where pp is a factor of the constant and qq is a factor of the leading coefficient.
p=±1,±2,±4p=±1,±2,±4
q=±1q=±1
Step 2
Find every combination of ±pq±pq. These are the possible roots of the polynomial function.
±1,±2,±4±1,±2,±4
Step 3
Substitute the possible roots one by one into the polynomial to find the actual roots. Simplify to check if the value is 00, which means it is a root.
(-2)2+4(-2)+4(−2)2+4(−2)+4
Step 4
Step 4.1
Simplify each term.
Step 4.1.1
Raise -2−2 to the power of 22.
4+4(-2)+44+4(−2)+4
Step 4.1.2
Multiply 44 by -2−2.
4-8+44−8+4
4-8+44−8+4
Step 4.2
Simplify by adding and subtracting.
Step 4.2.1
Subtract 88 from 44.
-4+4−4+4
Step 4.2.2
Add -4−4 and 44.
00
00
00
Step 5
Since -2−2 is a known root, divide the polynomial by x+2x+2 to find the quotient polynomial. This polynomial can then be used to find the remaining roots.
x2+4x+4x+2x2+4x+4x+2
Step 6
Step 6.1
Place the numbers representing the divisor and the dividend into a division-like configuration.
-2−2 | 11 | 44 | 44 |
Step 6.2
The first number in the dividend (1)(1) is put into the first position of the result area (below the horizontal line).
-2−2 | 11 | 44 | 44 |
11 |
Step 6.3
Multiply the newest entry in the result (1)(1) by the divisor (-2)(−2) and place the result of (-2)(−2) under the next term in the dividend (4)(4).
-2−2 | 11 | 44 | 44 |
-2−2 | |||
11 |
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.
-2−2 | 11 | 44 | 44 |
-2−2 | |||
11 | 22 |
Step 6.5
Multiply the newest entry in the result (2)(2) by the divisor (-2)(−2) and place the result of (-4)(−4) under the next term in the dividend (4)(4).
-2−2 | 11 | 44 | 44 |
-2−2 | -4−4 | ||
11 | 22 |
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.
-2−2 | 11 | 44 | 44 |
-2−2 | -4−4 | ||
11 | 22 | 00 |
Step 6.7
All numbers except the last become the coefficients of the quotient polynomial. The last value in the result line is the remainder.
(1)x+2(1)x+2
Step 6.8
Simplify the quotient polynomial.
x+2x+2
x+2x+2
Step 7
Subtract 22 from both sides of the equation.
x=-2x=−2
Step 8
The polynomial can be written as a set of linear factors.
x+2x+2
Step 9
These are the roots (zeros) of the polynomial x2+4x+4x2+4x+4.
x=-2x=−2
Step 10