Answer
$f^{-1}(x)=\dfrac{7-x}{5}$
Work Step by Step
$f(x)=7-5x$
Rewrite the expression as $y=7-5x$ and solve for $x$:
$y=7-5x$
Take $-5x$ to the left side and $y$ to the right side:
$5x=7-y$
Take the $5$ to divide the right side:
$x=\dfrac{7-y}{5}$
Interchange $x$ and $y$:
$y=\dfrac{7-x}{5}$
The inverse is $f^{-1}(x)=\dfrac{7-x}{5}$
