SOLUTION: Please help me solve this equation: Given f(x)= x^2 + 7 and g(x)= x^2 - 7, find f of g(x)

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Question 743599: Please help me solve this equation: Given f(x)= x^2 + 7 and g(x)= x^2 - 7, find f of g(x)
Found 2 solutions by josgarithmetic, tommyt3rd:
Answer by josgarithmetic(39616) About Me  (Show Source):
You can put this solution on YOUR website!
That means use g(x) as the input of f(x).
f%28___%29=%28___%29%5E2%2B7

Put g(x) into the missing place.

f%28g%28x%29%29=%28x%5E2-7%29%5E2%2B7, and you need to simplify the formula.


---EDITED for one misspelled word.---

Answer by tommyt3rd(5050) About Me  (Show Source):
You can put this solution on YOUR website!
f(g(x)) is a composition - we take a function as an input to another function.
f%28x%29=+x%5E2%2B7
and
g%28x%29=+x%5E2+-+7
g is the input of f so we replace g(x) with the expression - they are equal
f%28g%28x%29%29=+f%28x%5E2+-+7%29
f%28x%5E2+-+7%29=%28x%5E2+-+7%29%5E2%2B7
f%28g%28x%29%29=%28x%5E2+-+7%29%2A%28x%5E2+-+7%29%2B7
f%28g%28x%29%29=x%5E4-14x%5E2%2B49%2B7
f%28g%28x%29%29=x%5E4-14x%5E2%2B56