SOLUTION: Find all real zeros of f(x)=x^3+4x^2-5x-20

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Question 691011: Find all real zeros of f(x)=x^3+4x^2-5x-20
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
f(x)=x^3+4x^2-5x-20
set f(x) to zero and factor the right by grouping:
0=(x^3+4x^2)-(5x+20)
0=x^2(x+4)-5(x+4)
0=(x+4)(x^2-5)
x = {-4, -sqrt%285%29, sqrt%285%29)