10. Roots and Zeros
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If a is a zero of f(x)=0, then (x-a) is a factor of f(x).
f(x)=x^3-2x^2-13x-10
We want to write a polynomial function with integral coefficients so that f(x)=0 has the given zeros.
5, -2, -1
| Root | Factor |
|---|---|
| 5 | x-5 |
| -2 | x-(-2) |
| -1 | x-(-1) |
| Polynomial | f(x)= (x-5) [x-(-2)] [x-(-1)] |
Let's simplify the polynomial by applying the Distributive Property. For simplicity, we will start by multiplying the first two factors and then we will multiply the result by the last factor.
- (- a)=a
Distribute (x+2)
Distribute (x+1)