Question

Anyone know how to solve inverse of functions ? plz help

Answer 1

In each let y = f(x) and rearrange making x the subject

(7)

y = 3x + 9 ( subtract 9 from both sides )

3x = y - 9 ( divide both sides by 3 )

x = $\frac{y-9}{3}$

change y back into terms of x

$f^{-1}$(x) = $\frac{x-9}{3}$

(8)

y = 5x - 2

5x = y + 2 ( divide both sides by 5 )

x = $\frac{y+2}{5}$

$f^{-1}$(x) = $\frac{x+2}{5}$

(9)

y = - x + 2

x = 2 - y

$f^{-1}$(x) = 2 - x

(10)

y = - 4x + 3

4x = 3 - y ( divide both sides by 4 )

x = $\frac{3-y}{4}$

$f^{-1}$(x) = $\frac{3-x}{4}$

(11)

y = 0.5x - 2

0.5x = y + 2 ( divide both sides by 0.5 )

x = 2(y + 2)

$f^{-1}$(x) = 2x + 4

(12)

y = - 0.25x + 6

0.25x = 6 - y ( divide both sides by 0.25 )

x = 4(6 - y )

$f^{-1}$(x) = 24 - 4x