Question

2.7 Q2 Find an equation for the inverse function.

Answer 1

To find the inverse, we need to solve for x in term of f(x)

f(x) = 5x + 4
5x + 4 = f(x)

Solve for x
5x + 4 = f(x)
5x = f(x) - 4
  x = $\cfrac{f(x)-4}{5}$

x acts as the invers of f(x), and f(x) is the invers of x, so the inverse function will be
f⁻¹(x) = $\cfrac{x-4}{5}$