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Work Shown:
f(x) = 3x-1
f(x) = 3( x ) - 1
f( g(x) ) = 3( g(x) ) - 1 ... replace every x with g(x)
f( g(x) ) = 3(x^3-5x^2) - 1 ... plug in g(x) = x^3-5x^2
f( g(x) ) = 3x^3-15x^2-1
(f o g)(x) = 3x^3-15x^2-1
