What are the zeros of polynomial function f(x) = x3 + 9x2 + 20x?
Solution:
Given, the function is f(x) = x3 + 9x2 + 20x.
We have to find the zeros of the polynomial function.
Taking out x as common,
f(x) = x3 + 9x2 + 20x
f(x) = x(x2 + 9x + 20)
Factoring x2 + 9x + 20
= x2 + 4x + 5x + 20
= x(x + 4) + 5(x + 4)
= (x + 5)(x + 4)
So, f(x) = x(x + 5)(x + 4)
Let f(x) = 0
x(x + 5)(x + 4) = 0
x = 0
x + 5 = 0 ⇒ x = -5
x + 4 = 0 ⇒ x = -4
Therefore, the zeros of the polynomial function are x = 0, -4 and -5.
What are the zeros of polynomial function f(x) = x3 + 9x2 + 20x?
Summary:
The zeros of the polynomial function f(x) = x3 + 9x2 + 20x are x = 0, -4 and -5.
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