i need help finding the answer with step by step

Answer:
x= -1
Step-by-step explanation:
if
f(x) = -x-3
and
f(x) = -2
than
-x-3 = -2; add 3 to both sides
-x-3+3 = -2+3
-x = 1 ; multiply both sides by -1
x= -1