How do you find the inverse of $f(x) =1/4x+7$ ?

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Answer 1 · 2015-06-19T21:53:00

Write $y = 1/4x+7$

then rearrange to find $x = 4(y-7)$ , so the inverse function is:

$f^-1(y) = 4(y-7)$

Let $y = f(x) = 1/4x+7$

Subtract $7$ from both ends to get:

$y-7 = 1/4x$

Multiply both sides by $4$ to get:

$x = 4(y-7)$

This defines $x$ in terms of $y$ in such a way that the equation $y = 1/4x+7$ is satisfied, so it defines the inverse function:

$f^-1(y) = 4(y-7)$

How do you find the inverse of f(x) =1/4x+7f(x) =1/4x+7?