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Answer the following: If f(x) = 2x-15x-2,x≠52 show that (f ° f) (x) = x

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Question

Answer the following:

If f(x) = `(2x - 1)/(5x - 2), x ≠ 5/2` show that (f ° f) (x) = x

Sum
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Solution

(f ° f) (x) = f[f(x)]

= `"f"[(2x - 1)/(5x - 2)]`

= `(2((2x - 1)/(5x - 2)) - 1)/(5((2x - 1)/(5x - 2)) - 2)`

= `(2(2x - 1) - (5x - 2))/(5(2x - 1) - 2(5x - 2)`

= `(4x - 2 - 5x + 2)/(10x - 5 - 10x + 4)`

= `(-x)/(-1)`

= x

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Chapter 6: Functions - Miscellaneous Exercise 6.2 [Page 130]

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