SOLUTION: Let f (x) = 3x2 + 9 and g(x) = x – 4. (a) Find the composite function (f*g)(x) and simplify. (b) Find (f*g)(−1)

Algebra ->  Functions -> SOLUTION: Let f (x) = 3x2 + 9 and g(x) = x – 4. (a) Find the composite function (f*g)(x) and simplify. (b) Find (f*g)(−1)      Log On


   

Question 1126047: Let f (x) = 3x2 + 9 and g(x) = x – 4.
(a) Find the composite function (f*g)(x) and simplify.
(b) Find (f*g)(−1)
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
Let
f%28x%29=3x%5E2+%2B+9 and
g%28x%29+=+x+%96+4
(a) Find the composite function
%28f%2Ag%29%28x%29=%283x%5E2+%2B+9%29%28x-+4%29
%28f%2Ag%29%28x%29=3x%5E3-12x%5E2+%2B+9x+%96+36


(b)
%28f%2Ag%29%28-1%29=3%28-1%29%5E3-12%28-1%29%5E2+%2B+9%28-1%29+%96+36
%28f%2Ag%29%28-1%29=-3-12+-+9+%96+36
%28f%2Ag%29%28-1%29=-60