SOLUTION: Find f(g(-1)), given the following functions: f(x)=x^2+x-3 f(x)=9x+9

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: Find f(g(-1)), given the following functions: f(x)=x^2+x-3 f(x)=9x+9      Log On


   

Question 459981: Find f(g(-1)), given the following functions:
f(x)=x^2+x-3
f(x)=9x+9
Answer by Gogonati(855) About Me  (Show Source):
You can put this solution on YOUR website!
First we find the composite function f%28g%28x%29%29=%289x%2B9%29%5E2%2Bx-3 simplifying it we
get:f%28g%28x%29%29=81%28x%2B1%29%5E2%2B%28x-3%29 and f%28g%28-1%29%29=81%281-1%29%5E2%2B%281-3%29.
f%28g%28-1%29%29=-2.