SOLUTION: Hi: I have a composition problem that I'm uncertain how to figure out. If someone could give me directions, I'd be grateful. Cheers! Angela Problem: Find the requested funct

Algebra ->  Equations -> SOLUTION: Hi: I have a composition problem that I'm uncertain how to figure out. If someone could give me directions, I'd be grateful. Cheers! Angela Problem: Find the requested funct      Log On


   

Question 589964: Hi: I have a composition problem that I'm uncertain how to figure out. If someone could give me directions, I'd be grateful. Cheers! Angela
Problem:
Find the requested function value.
"find (f o g)(8) when f(x)= 4x+2 and g(x)=-7x^2+4x+7"
Wouldn't I put the 8 in the place of all of the x's? Then what would I do?

Found 2 solutions by solver91311, richard1234:
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


You don't put in the value of 8 until you have created the function composition. Substitute the definition of for every in the definition of . Put another way, interpret as . Once you simplify, THEN substitute 8 for in the simplified definition of .

John

My calculator said it, I believe it, that settles it
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Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
(f o g)(8) is also read f(g(8)), which you should interpret it as "f of 'g of 8'". That is, find g(8) first, then replace the value of g(8) into f to find f(g(8)).