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Question -

If f(x) = (4x + 3)/ (6x – 4), x ≠ (2/3) show that fof(x) = x, for all x ≠ (2/3). What is the inverse of f?



Answer -

It is given that f(x)= (4x + 3)/ (6x – 4), x ≠ 2/3

Now we have to showfof(x) = x

(fof)(x) = f (f(x))

= f ((4x+ 3)/ (6x –4))

= (4((4x + 3)/ (6x-4)) + 3)/ (6 ((4x +3)/ (6x – 4)) – 4)

= (16x + 12 + 18x –12)/ (24x + 18 – 24x + 16)

= (34x)/ (34)

= x

Therefore, fof(x) = xfor all x ≠ 2/3

=> fof = 1

Hence, the givenfunction f is invertible and the inverseof f is f itself.

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