Question

How do I justify my steps? 24 - x = -16

Answer 1

@CANDESTIEL 24 - x = -16
-x+24=-16
-x + 24 - 24 = -16 - 24
-x = -40
-x/-1 = -40/-1
x = 40

Answer 2

Alrighty, we have 24 - x = -16
24 - x = -16
+16 +16
________________
40 - x = 0
+x +x
______________
40 = x

Justification:
You add 16 to both sides in order to get the numbers together and isolate the x. After this, we add x to both sides to isolate the variable. the justification for all of this is merely to solve for x.
Hope I helped.