# Thread: Solve a cubic

1. ## Solve a cubic

I need solve this equation

$x^3+2x^2+2x+1=0$

2. ## Re: Solve equation

Originally Posted by Mhmh96
I also need solve this equation ^
Can you find a value of x that makes the LHS = 0?

3. ## Re: Solve equation

The factors of $x^3+2x^2+2x+1$ are $(1 + x) (1 + x + x^2)$.

Now, roots of the equation can be found.

4. ## Re: Solve equation

Originally Posted by sbhatnagar
The factors of $x^3+2x^2+2x+1$ are $(1 + x) (1 + x + x^2)$.

Now, roots of the equation can be found.
Correct though.
@ Mhmh96

You can use factor theorem to factorize this equation : x^3+2x^2+2x+1
What are the factors of 1 ?
1 AND -1
-1 is satisfying the equation to 0
f(-1) =0
so
x+1 is factor of x^3+2x^2+2x+1
Now use division method .
Quotient will be
(1 + x + x^2)

So x^3+2x^2+2x+1 = (x+1)(1 + x + x^2)