Answer:
x = -1 and x = 4
Step-by-step explanation:
Step 1: Get everything to one side of the equation so it's set equal to zero..
-x² + 4x = x - 4 becomes...
-x² + 3x + 4 = 0 (subtract x and add 4 to both sides)
x² - 3x - 4 = 0 (divide both sides by -1, we want the x² term to be positive)
(x - 4)(x + 1) = 0 (factor)
so
x - 4 = 0, then x = 4
and
x + 1 = 0, then x = -1
