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Intermediate Algebra

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Please help with the below. I know the answer I need help figuring out how to get the answer I am obviously doing something wrong, because I come up with a different answer that what I am supposed to. Here it is: F(X)3Xsquared-5X+1 The correct answer is 12Xsquared-70X+101, the answer I come up with is 12Xsquared-65X+76. This is a composition AKA substitution problem. Here are my notes: F(X)3Xsquared-5X+1
g(X)2X-5
(Fog)(X)F(g(x))
3 (2X-5)-5X+1
6X-15-5X+1
2(3Xsquared-5X+1)-5
6Xsquared-10X+2-5
6Xsquared-10X-3

  • Intermediate Algebra -

    f(x) = 3x^2-5x+1
    g(x) = 2x-5

    (fog)(x) = f(g) = 3g^2-5g+1
    = 3(2x-5)^2 - 5(2x-5) + 1
    = 3(4x^2-20x+25) - 5(2x-5) + 1
    = 12x^2-60x+75-10x+25+1
    = 12x^2-70x+101

    Looks like you messed up on the -5(2x-5) part

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