Me solve this. i’m really confused on it!

Y will have the same value as x, since if a function f(x) is mapping x onto y then the inverse of f(x) will map y back to x
well, i guess...

They want you to put your own equation in the box and solve so what you van do is:
f^-1(x)=4x+y
Then plug in the "x" numbers and solve.
(-10)=4(-10)+y
y=30

   x        y
-10       30
 -5        15
  0         0
  5       -15
 10      -30

I hope this helps

3cm and 6 and 9 cm that a possibility of that question