Question 205044
Given:
{{{f(x) = 2x/7 +4}}} find the inverse. First, replace {{{f(x)}}} with {{{y}}}
{{{y = 2x/7 +4}}} Now exchange the variables x and y.
{{{x = 2y/7+4}}} then solve this equation for y. Subtract 4 from both sides.
{{{x-4 = 2y/7}}} Multiply both sides by 7.
{{{7x-28 = 2y}}} and divide both sides by 2.
{{{y = (7x-28)/2}}} Finally, replace {{{y}}} with {{{f^-1(x)}}}
{{{highlight(f^-1(x) = (7x-28)/2)}}}
By the way, notice that it is {{{f^-1(x)}}} and not {{{f^-1(y)}}}