Find the sum and choose the correct answer.

2n^3 + 4n^2 - 7 and -n^3 + 8n - 9

-n^3 - 4n^2 - 8n - 16
n^3 + 4n^2 + 8n - 16
n^3 + 4n^2 + 8n + 16
3n^3 + 4n^2 + 8n - 2

Question

Find the sum and choose the correct answer.

2n^3 + 4n^2 - 7 and -n^3 + 8n - 9

-n^3 - 4n^2 - 8n - 16
n^3 + 4n^2 + 8n - 16
n^3 + 4n^2 + 8n + 16
3n^3 + 4n^2 + 8n - 2

anonymous · Answer

put together those that have the same variable and exponents

anonymous · Answer

what do you mean?

anonymous · Answer

do you know what variables and exponents are?

anonymous · Answer

so its the third one?

anonymous · Answer

$\huge ax^n $ 

the above expression
a is your coefficient or magnitude 
x is your variable 
n is your exponents 

when adding or subtracting expressions, you can only add and subtract those that have the same variable AND exponents