Answer:
-54
Step-by-step explanation:
Add 18 to both sides of the equation.
x -18 +18 = -72 +18
x = -54 . . . . the solution to the equation
_____
Additional comment
This is called a "one-step" equation. The one step needed to solve it is to add the opposite of the constant that is on the same side of the equal sign as the variable. That constant is -18. Its opposite is 18, so 18 is what we add.
Anything we do to one side of the equation must also be done to the other side, so we must add 18 to both sides of the equation.
