Answer:
f(1) = -8
Step-by-step explanation:
Apparently, you want the argument of the function such that the function value is -8. Fill in the given information and solve for x:
-8 = -7x -1
-7 = -7x . . . . add 1
1 = x . . . . . . . divide by -7
Now, you know that ...
f(1) = -8
