Question

A student was asked to solve 4x^2−12x=0
by factoring out the GCF.

At what step did the student first make an error?

Given: 4x^2−12x=0

Step 1: 4x(x+3)=0

Step 2: 4x=0 and x+3=0

Step 3: x=0 and x=−3

(1 point)

Answer 1

Error occurs at Step 1.

Correct factoring: 4x^2 − 12x = 4x(x − 3), not 4x(x + 3).
So the solutions are 4x = 0 → x = 0 and x − 3 = 0 → x = 3.