SOLUTION: If f(x)=3x^2+1 and g(x)=2x+2, then (fog^-1)(2) = ...I don't understand how to find the answer. I know that "fog" means f of g, but I don't know how to plug that in.

Algebra ->  Trigonometry-basics -> SOLUTION: If f(x)=3x^2+1 and g(x)=2x+2, then (fog^-1)(2) = ...I don't understand how to find the answer. I know that "fog" means f of g, but I don't know how to plug that in.      Log On


   



Question 698148: If f(x)=3x^2+1 and g(x)=2x+2, then (fog^-1)(2) =

...I don't understand how to find the answer.
I know that "fog" means f of g, but I don't know how to plug that in.

Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
To get f of g :
take the info for g(x) (in this case 2x+2) and plug that into the equation for f(x).
So every place you see an 'x' in the f(x) equation, plug in '2x+2' (which is g(x)
f%28g%28x%29%29+=+3%28g%28x%29%29%5E2+%2B+1
f%28g%28x%29%29+=+3%282x%2B2%29%5E2+%2B+1
f%28g%28x%29%29+=+3%284x%5E2+%2B+8x+%2B+4%29+%2B+1
f%28g%28x%29%29+=+12x%5E2+%2B+24x+%2B+12+%2B+1
f%28g%28x%29%29+=+12x%5E2+%2B+24x+%2B+13