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Answer the following: If f(x) = x+34x-5, g(x) = 3+5x4x-1 then show that (f ° g) (x) = x

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Question

Answer the following:

If f(x) = `(x + 3)/(4x - 5)`, g(x) = `(3 + 5x)/(4x - 1)` then show that (f ° g) (x) = x

Sum
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Solution

f(x) = `(x + 3)/(4x - 5)`, g(x) = `(3 + 5x)/(4x - 1)`

(f ° g) (x) = f(g(x))

= `"f"((3 + 5x)/(4x - 1))`

= `((3 + 5x)/(4x - 1) + 3)/(4((3 + 5x)/(4x - 1)) - 5)`

= `(3 + 5x + 12x - 3)/(12 + 20x - 20x + 5)`

= `(17x)/17`

= x

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Chapter 6: Functions - Miscellaneous Exercise 6.2 [Page 131]

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