Answer:
x = -4
Step-by-step explanation:
(x - 5) (x + 4) = x^2 + 4x
If you expand this, you get:
x^2 - x - 20 = x^2 + 4x
graph similar terms together, the x^2 disappears:
-20 = 5x
x = -20/5 = -4
