Question

the question is:

-3x-2z-7
if x=3 and z= -1

i did the the question and got the answer - 14 ....but the answer key that i got say -20....can anyone help me... with this plz....

Answer 1

-3(3) -2(-1) - 7

-9 +2 -7
-7 - 7
-14