Solve the function... MEDAL!

Question

calculusxy · Answer

$f(n) = 3n^2 - 2n$
$g(n) = -n-1$
Find $f(3 + n) - 5g(3 + n)$

calculusxy · Answer

I got the answer of 3n^2 + 21n + 41

calculusxy · Answer

@Directrix

daniellelovee · Answer

you were very close to the actual answer but that is not it

calculusxy · Answer

is it 3n^2 + 21n + 47

daniellelovee · Answer

no sorry but you are on the right track :)

calculusxy · Answer

do i need to factor this now?

daniellelovee · Answer

no can you show me the work you did so that I can tell you where you messed up please? :)

calculusxy · Answer

ok

calculusxy · Answer

f(3+n) = 3(3+n)^2 - 2(3+n)
3(n^2 + 6n + 9) - 6 - 2n
3n^2 + 18n + 27 - 6 - 2n
3n^2 + 16n + 21

g(3+n) = -(3+n) - 1
-3 - n - 1
-n - 4
-5(-n-4) = 5n + 20

3n^2 + 16n + 21 + 5n + 20 = 
3n^2 + 21n + 41

calculusxy · Answer

@Daniellelovee

daniellelovee · Answer

im sorry can you give me a second I'll be right back im translating something for my mom

calculusxy · Answer

ok

directrix · Answer

I ran this -->  3*(3+n)^2 -2*(3+n) - 5*(-(3+n)-1)=

through WolframAlpha.com

and got a result of 3n^2 + 21n + 41

which is the same as your answer.

@calculusxy

calculusxy · Answer

ok thanks
and i want to understand how to evaluate|dw:1461099942091:dw|