Question

A student said that x = 4 was not a solution to the question 3(x -6) = -8

Here is their work:
3(x -6) = -8
3 (4 -6) = -8
12 -6 = -8
6≠ -8
so x = 4 is not a solution

Did the student substitute x=4 correctly? How do you know?

Did the student simplify with Order of Operations correctly? How do you know?

If you try the problem, what do you get when you substitute x=4 into the equation?

Answer 1

Explanation:

3 (4 -6) = -8 is correct. The next step is to combine 4 and -6, obtaining

3(-2)

and this 3(-2) should equal -6, which is not the same as -8.

3(4 - 6) = 12 - 18, which differs from the student's solution. This is the reason for the wrong answer.