SOLUTION: If f(x) = x3 + 4 and g(x) = x + 3, find [g • f](2)

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Question 3695: If f(x) = x3 + 4 and g(x) = x + 3, find [g • f](2)
Answer by longjonsilver(2297) About Me  (Show Source):
You can put this solution on YOUR website!
gf(x) only means put the value of x into the function f(x), to get an answer, then put that into the function g(x), like so:

f(x) = x%5E3+%2B+4 --> i assume this is a cube? I am not 100% sure though from your notation.
g(x) = x + 3

so, gf(x) is g%28x%5E3%2B4%29 which becomes %28x%5E3%2B4%29%2B3 ie x%5E3%2B7

so gf(2) = 2%5E3+%2B+7
gf(2) = 8+7
gf(2) = 15

Now, strictly, we didn't need to find gf(x) first...i just did that to show you the process. If you just need to find the numerical value, then do the following:
as f(x) = x%5E3%2B4
f(2) = 2%5E3%2B4
f(2) = 8+4
f(2) = 12
so then g(12) -- since f(2) is equivalent to 12 -- is 12+3

g(12) = 15.... same answer :-)

Hope this helps

jon