Question

`f(x) = (21 - 6x)/(5)`
find

`{f}^( - 1) (x)`
​

Answer 1

-5/6x + 7/2 = y

Explanation:

f(x) = (21 -6x) /5

y = 1/5 (21 -6x)

To find the inverse exchange x and y

x = 1/5 (21-6y)

Solve for y

Multiply each side by 5

5x = 5* 1/5 (21-6y)

5x = (21-6y)

Subtract 21 from each side

5x -21= (21-21-6y)

5x-21 = -6y

Divide each side by -6

5/-6x-21/-6 = -6/-6y

-5/6x + 7/2 = y