SOLUTION: Find the real or imaginary solution of each equation by factoring. 1: X^3 + 2x^2 + 5x + 10 = 0

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Find the real or imaginary solution of each equation by factoring. 1: X^3 + 2x^2 + 5x + 10 = 0       Log On


   

Question 956787: Find the real or imaginary solution of each equation by factoring.
1: X^3 + 2x^2 + 5x + 10 = 0
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
graph%28300%2C300%2C-5%2C5%2C-5%2C5%2Cx%5E3%2B2x%5E2%2B5x%2B10%29
Looks like x=-2 is a root.
Verifying,
%28-2%29%5E3%2B2%28-2%29%5E2%2B5%28-2%29%2B10=0
-8%2B8-10%2B10=0
0=0
True, so x=-2 is a root.
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So x%2B2 is a factor.
Use polynomial long division to divide out x%2B2.
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x%5E3%2B2x%5E2%2B5x%2B10=%28x%2B2%29%28x%5E2%2B5%29
So then,
x%5E2%2B5=0
x%5E2=-5
x=0+%2B-+sqrt%285%29i