student was asked to solve 4x2−12x=0

Question

by factoring out the GCF.

At what step did the student first make an error?

Given: 4x2−12x=0


Step 1: 4x(x−3)=0


Step 2: 4x=0 and x−3=0


Step 3: x=0 and x=−3


(1 point)
Responses

Step 1
Step 1

Step 2
Step 2

Step 3

Answer 1

The student made an error in Step 3. The factorization in Step 2 is correct, where they set \( 4x = 0 \) and \( x - 3 = 0 \). However, the solutions derived from Step 3 are incorrect.

From \( 4x = 0 \), the solution is \( x = 0 \), which is correct. But from \( x - 3 = 0 \), the solution is \( x = 3 \), not \( x = -3 \).

So, the answer is Step 3.