Q:

Confirm that f and g are inverses by showing that f(g(x)) = x and g(f(x)) = x. f(x) = quantity x minus eight divided by quantity x plus seven and g(x) = quantity negative seven x minus eight divided by quantity x minus one.

Accepted Solution

A:
Answer:[tex]g(f(x))=\frac{-7(\frac{x-8}{x+7})-8}{(\frac{x-8}{x+7})-1}\\\\g(f(x))=x[/tex][tex]f(g(x))=\frac{(\frac{-7x-8}{x-1})-8}{(\frac{-7x-8}{x-1})+7}\\\\\\f(g(x))=x[/tex]Step-by-step explanation:First we write the function f(x)[tex]f(x) = \frac{x-8}{x+7}[/tex]Now we write the function g(x)[tex]g(x)=\frac{-7x-8}{x-1}[/tex]First we find [tex]f (g (x))[/tex]To find [tex]f(g(x))[/tex] you must enter the function g(x) into the function f(x) by making [tex]x = g (x)[/tex][tex]f(g(x))=\frac{(\frac{-7x-8}{x-1})-8}{(\frac{-7x-8}{x-1})+7}[/tex]Now we simplify the expression[tex]f(g(x))=\frac{(\frac{-7x-8}{x-1})-8}{(\frac{-7x-8}{x-1})+7}\\\\\\f(g(x))=\frac{(\frac{-7x-8-8(x-1)}{x-1})}{(\frac{-7x-8+7(x-1)}{x-1})}\\\\\\f(g(x))=\frac{-7x-8-8(x-1)}{-7x-8+7(x-1)}\\\\\\f(g(x))=\frac{-7x-8-8x+8}{-7x-8+7x-7}\\\\\\f(g(x))=\frac{-15x}{-15}\\\\\\f(g(x))=x[/tex]Now we find [tex]g(f(x))[/tex] doing [tex]x = f (x)[/tex][tex]g(f(x))=\frac{-7(\frac{x-8}{x+7})-8}{(\frac{x-8}{x+7})-1}[/tex]Now we simplify the expression[tex]g(f(x))=\frac{-7(\frac{x-8}{x+7})-8}{(\frac{x-8}{x+7})-1}\\\\\\\g(f(x))=\frac{(\frac{-7x+56}{x+7})-8}{(\frac{x-8-(x+7)}{x+7})}\\\\\\g(f(x))=\frac{(\frac{-7x+56-8(x+7)}{x+7})}{(\frac{x-8-(x+7)}{x+7})}\\\\\\g(f(x))=\frac{-7x+56-8(x+7)}{x-8-(x+7)}\\\\g(f(x))=\frac{-7x+56-8x-56}{x-8-x-7}\\\\g(f(x))=\frac{-15x}{-15}\\\\g(f(x))=x[/tex]