Given f(x) = -x - 2, find x when f(x) = 12.

Replace all x’s in the original problem with the f(x) in the given. In this case, f(x)=12 so you would plug that into the original. This would make it:
f(x) = -(12) - 2
f(x) = -12 + -2
X= -14

The answers are 20,30,80,180,960,890,1230,4560. on the first row