Question

Given the function f(x) = 5(x+4) − 6, solve for the inverse function when x = 19..

Answer 1

f(x) = 5 ( x + 4) - 6
y = 5 (x + 4)

interchange x and y and then solve for y
x = 5 (y + 4)


`(x)/(5) = y + 4`


`y = (x)/(5) - 4`

∴
`f ^(-1) (x) = (x)/(5) - 4`


Solve for x= 19 for the inverse found


`f ^(-1) (19) = (19)/(5) - 4`


`f ^(-1) (19) = - (1)/(5)`