f(x) = 7x + 5
g(x) = x - 1
f(g(x)) = 7 (x - 1) + 5 = 7x - 7 + 5 = 7x - 2 = h(x)
So...for h(x) write y
y = 7x - 2 add 2 to both sides
y + 2 = 7x dicvide both sides by 7
(y + 2) / 7 = x "swap" x and y
(x + 2)/ 7 = y for y , write h-1(x)
So
h-1 ( x) = (x + 2) / 7