Examples
x2-1
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
q=±1
Step 2
Find every combination of ±pq. These are the possible roots of the polynomial function.
±1
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.
(1)2-1
Step 4
Step 4.1
One to any power is one.
1-1
Step 4.2
Subtract 1 from 1.
0
0
Step 5
Since 1 is a known root, divide the polynomial by x-1 to find the quotient polynomial. This polynomial can then be used to find the remaining roots.
x2-1x-1
Step 6
Step 6.1
Place the numbers representing the divisor and the dividend into a division-like configuration.
1 | 1 | 0 | -1 |
Step 6.2
The first number in the dividend (1) is put into the first position of the result area (below the horizontal line).
1 | 1 | 0 | -1 |
1 |
Step 6.3
Multiply the newest entry in the result (1) by the divisor (1) and place the result of (1) under the next term in the dividend (0).
1 | 1 | 0 | -1 |
1 | |||
1 |
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.
1 | 1 | 0 | -1 |
1 | |||
1 | 1 |
Step 6.5
Multiply the newest entry in the result (1) by the divisor (1) and place the result of (1) under the next term in the dividend (-1).
1 | 1 | 0 | -1 |
1 | 1 | ||
1 | 1 |
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.
1 | 1 | 0 | -1 |
1 | 1 | ||
1 | 1 | 0 |
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+1
Step 6.8
Simplify the quotient polynomial.
x+1
x+1
Step 7
Subtract 1 from both sides of the equation.
x=-1
Step 8
The polynomial can be written as a set of linear factors.
(x-1)(x+1)
Step 9
These are the roots (zeros) of the polynomial x2-1.
x=1,-1
Step 10