Intermediate Algebra
posted by BL on .
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)3Xsquared5X+1 The correct answer is 12Xsquared70X+101, the answer I come up with is 12Xsquared65X+76. This is a composition AKA substitution problem. Here are my notes: F(X)3Xsquared5X+1
g(X)2X5
(Fog)(X)F(g(x))
3 (2X5)5X+1
6X155X+1
2(3Xsquared5X+1)5
6Xsquared10X+25
6Xsquared10X3

f(x) = 3x^25x+1
g(x) = 2x5
(fog)(x) = f(g) = 3g^25g+1
= 3(2x5)^2  5(2x5) + 1
= 3(4x^220x+25)  5(2x5) + 1
= 12x^260x+7510x+25+1
= 12x^270x+101
Looks like you messed up on the 5(2x5) part