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

1 Answer

The answer is:
#x = 0# or # x = - 3#

Explanation:

Let's do this in steps

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

Next, factor out common coefficients 3.
#(3) (x^2 + 3x) = 0#

By factoring (as you requested), factor out x from the parentheses.
#(3x) (x + 3) = 0#

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