# How do you solve 3x^2 = -9x by factoring?

Mar 20, 2018

$x = 0$ or $x = - 3$

#### Explanation:

Let's do this in steps

First, move all instances of "x" to one side of the equation.
$3 {x}^{2} = - 9 x$
$3 {x}^{2} + 9 x = 0$

Next, factor out common coefficients 3.
$\left(3\right) \left({x}^{2} + 3 x\right) = 0$

By factoring (as you requested), factor out x from the parentheses.
$\left(3 x\right) \left(x + 3\right) = 0$

At this step, you will be able to find both answers (as this is a quadratic equation).
When $\left(3 x\right) = 0$,
$x = \frac{0}{3}$ -> Divide both sides by 3 to get x on the left
$x = 0$
When $\left(x + 3\right) = 0$
$x = - 3$ -> Minus both sides by 3 to get x on the left