Question

what is the inverse function of 7x+4 ( this is a one to one function)

??

Answer 1

it is one to one because the graph is a line

Answer 2

suppose you had to solve
\[7x+4=25\] what would you do? subtract 4 then divide by 7
that is what the inverse function does, find the input when you know the output, so it is
\[f^{-1}(x)=\frac{x-4}{7}\]