contestada

Mia is factoring the polynomial
x^2+4x−12. She uses the steps shown.

x^2+4x−12
Step 1
x^2+6x−2x−12
Step 2
(x^2+6x)−(2x+12)
Step 3
x(x+6)−2(x+6)
Step 4
(x+6)(x+2)
In which step did Mia make an error?