Given:
-(5z + 12) = 18
First Step:
Use distributive property and expand the parenthesis.
Also distribute the negative symbol
-5z + (-12) = 18
-5z - 12 = 18
Second Step:
Add 12 to both sides of the equation.
-5z - 12 + 12 = 18 + 12
-5z = 30
Third Step:
Divide both sides by -5
ANSWER:
z = -6