Question

Find the zeros of the polynomial function.

f(x) = x3 + 5x2 - 4x - 20

A. x = -5, x = 4

B. x = -2, x = 2

C. x = -5, x = -2, x = 2

D. x = 5, x = -2, x = 2

Answer 1

Factor by grouping:
\[x^3+5x^2-4x-20=0\\
x^2(x+5)-4(x+5)=0\\
(x^2-4)(x+5)=0\]

Answer 2

ok cool so whats next

Answer 3

Do you know how to solve this? If you keep factoring, you get
\[(x+2)(x-2)(x+5)=0\]
From here, you split up into three equations and solve for x:
\[\begin{matrix}x+2=0,&x-2=0,&x+5=0\end{matrix}\]

Answer 4

is it C @SithsAndGiggles

Answer 5

Yes

Answer 6

wow thanks i think that deserves a medal lol @SithsAndGiggles

Answer 7

You're welcome