Question

which reason is incorrect?
4x + 5x + 12 = -6 (given)
9x + 12 = -6 (simplify)
9x = -18 (subtraction)
x = -2 (addition)

Answer 1

The last one is incorrect. The correct answer is division. They divided 9 on both sides.

Answer 2

the SUBTRACTION is incorrect. you’re suppose to do the opposite and add 6 to 12 and get 18. then you do 18/9 and get 2!