SOLUTION: if f(x)=x^2+2x find f(a+3)

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Question 293645: if f(x)=x^2+2x
find f(a+3)
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
f%28x%29=x%5E2%2B2x Start with the given function.


f%28a%2B3%29=%28a%2B3%29%5E2%2B2%28a%2B3%29 Plug in x=a%2B3


f%28a%2B3%29=a%5E2%2B6a%2B9%2B2%28a%2B3%29 FOIL


f%28a%2B3%29=a%5E2%2B6a%2B9%2B2a%2B6 Distribute.


f%28a%2B3%29=a%5E2%2B8a%2B15 Combine like terms.