Question

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

A) -n^3-4^2-8n-16

B) n^3+4n^2+8n+16

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

D) 3 n^3+4n^4+8n-2

Answer 1

C)
`n^3+4n^2+8n-16`

Explanation:

`2n^3+4n^2-7+(-n^3)+8n-9=\\n^3+4n^2-7+8n-9=\\n^3+4n^2+8n-9-7=\\n^3+4n^2+8n-16`

(Just combine like terms)

Only C)
`n^3+4n^2+8n-16` fits our answer.

Answer 2

Answer:

`{n}^(3) + 4 {n}^(2) + 8n - 16`

Option C is the right option

Solution,

`2 {n}^(3) + 4 {n}^(2) - 7 + ( - {n}^(3) + 8n - 9) \\ = 2 {n}^(3) + 4 {n}^(2) - 7 - {n}^(3) + 8n - 9 \\`

combine like terms

`2 {n}^(3) - {n}^(3) + 4 {n}^(2) + 8n - 7 - 9 \\simplify \\ = {n}^(3) + 4 {n}^(2) + 8n - 16`

hope this helps...

Good luck on your assignment..