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

4n+21+2n+21= -4 
 well first you've got to put teh like terms together so... 
 4n+2n+21+21= -4 
 now you have to solve it by ading the like terms so... 
 6n+42= -4 
 now you've got to do backtracking. yo always take the sign before a number with you while you do backtracking. so instead of doing 42 - 4 > you have to do -42 - 4 which gives you the answer of -46. 
 so now it is 6n= -46 
 all you got to do now is 6 divided by -46 
 which gives you -7 and 4/6 
 therefore : n= -7 4/6 got it from yahoo answers