Question 941424
Given the function f(x) = (2x-4)/x
 and x belongs to the real numbers and x does not equal zero, find 
f^2(x) 
The answer given in the textbook is 4 / (2-x). 
I can not understand how to get this answer.
 I think f^2(x) = ff(x) but I don't know how to do this function.
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fof(x) = f[(2x-4)/x]
So, replace "x" in f(x) with (2x-4)/x to get 
= [2[(2x-4)/x)-4]/[(2x-4)/x]
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= [(4x-8)/x - 8]/[(2x-4)/x]
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= [(4x-8-8x]/x] / [(2x-4)/x]
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= [(-4x-8)/x] / [(2x-4)/x]
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Invert the denominator and multiply to get::
= [-4(x+2)/x] * x/[2(x-2)]
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Cancel "x" and "2" to get::
= -2(x+2)/(x-2)
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Cheers,
Stan H.
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