find the formula for the inverse, f(x) = x + 7.
If you are refering to the inverse function
f^-1(x) = x - 7
f^-1 is the function that gives you back x when you plug in y as the variable.
f^-1(x) = x - 7
f^-1 is the function that gives you back x when you plug in y as the variable.