The function is saying if x is > -4 use the first equation.
If x is ≤4 then use the 2nd equation.
Then you are given (f-6), the value inside the parenthesis is the x value.
-6 is less than -4, so now using the 2nd equation, replace x with -6 and solve:
-(x-1) becomes -(-6-1) becomes -(-7) which becomes 7.
The answer is A. 7
