Example 4:
(a) If f:x→x−2, find f−1(5),
(b) if f:x→x+9x−5, x≠5, find f−1(3).
Solution:
(a)
f (x) = x– 2
Let y = f -1 (5)
f (y) = 5
y – 2 = 5
y = 7
therefore, f -1 (5) = 7
(b)
f(x)=x+9x−5Let y=f−1(3)f(y)=3y+9y−5=3y+9=3y−152y=24y=12∴