Answer:
18
Explanation:
We have the expression
3z-3
We know that z=7. Therefore, we can substitute 7 in for z.
z=7
3(7)-3
Now, solve according to PEMDAS (Parentheses, Exponents, Multiplication, Division, Addition, Subtraction)
Multiply 3 and 7 first.
21-3
Subtract 3 from 21.
18
The value of 3z-3 when z=7 is 18