#1**+2 **

x(x - 4) = 12

First "unfactor" the left side.

x*x - x*4 = 12

x^{2} - 4x = 12

Subtract 12 from both sides.

x^{2} - 4x - 12 = 0

Factor it back with the 12 included this time.

**(x - 6)(x + 2) = 0**

If that is all the instructions say do, stop there...but if you want to solve for x, set each factor = 0

x - 6 = 0 and x + 2 = 0

x = 6 and x = -2

hectictar
Mar 30, 2017