Question

Hyung-eun is solving the quadratic equation x^2 - 4x - 12 = 0 by grouping. Her work is shown
below. At which step does Hyung-eun first make an error?
x^2-4x - 12=0
х(x-6) +2 (x-6) = 0
Step1: x^2 +(-6x) +2x-12= 0
Step 2: (x^2 + (-6x)) + (2x-12) = 0
Step 3: x (x+(-6)) +2 (x-6) = 0
Step 4: (x + 6) (x-2) = 0
Step 5: x + 6 = 0 or x - 2 = 0
x = -6 or x =2
(1 point)
Step 4
Step 2
Step 1
Step 3

Answer 1

Step 4.

Reason: From x(x-6)+2(x-6) you factor (x-6) to get (x+2)(x-6). Hyung-eun wrote (x+6)(x-2), which is incorrect.