Question 35505
f(x) = 2x + 1
g(x) = x^2 - 4
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(fg)(x)=(2x+1)(x^2-4)=2x^3+x^2-8x-4
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(g of f)(x) = (2x+1)^2 - 4 
= (2x+1)(2x+1) - 4 = 4x^2 + 4x + 1 - 4 = 4x^2 + 4x - 3