Given f (x) = the quantity of x minus 5, divided by 3, solve for f-1 (3).

-1

14

18

21

Remark

Let f (x) = y must to make it easier to write.

Equation

Original Equation: y = (x - 5) / 3

Inverse

Interchange the x and y. You get x = (y - 5) / 3

Solve for y in the inverse.

x = (y - 5) / 3 Multiply by 3

3x = y - 5 Add 5 to both sides.

3x + 5 = y

substitute f1 (x) back into the equation.

3x + 5 = f (x) Now put in 3 for x

f (3) = 3x + 5

f (3) = 3*3 + 5

f (3) = 14 <<< Answer