Question

Add: (3x2 - 5x + 6) + (9 - 8x - 4x2)

A)
12x2 - 13x + 2


B)
7x2 + 3x - 3


C)
7x2 - 13x + 15


D)
-x2 - 3x + 15


E)
-x2 - 13x + 15

Answer 1

Answer:
`E) -x^2-13x+15` .

Explanation:

To add :
`(3x^2 - 5x + 6) + (9 - 8x - 4x^2)`

`=3x^2 - 5x + 6+ 9 - 8x - 4x^2`

This can be re-written as :

`3x^2-4x^2-5x-8x+6+9`

Combine like terms as

`=(3-4)x^2-(5+8)x+15\ \ [\because (-)(+)=(-)]\\\\=-x^2-13x+15`

Therefore,
`(3x^2 - 5x + 6) + (9 - 8x - 4x^2)=-x^2-13x+15`

Hence, the correct option is
`E) -x^2-13x+15` .

Answer 2

Add: (3x2 - 5x + 6) + (9 - 8x - 4x2)
The givens should be arranged first before we can start answering.
3x2 - 5x + 6 plus
-4x2 - 8x + 9
= -x2 - 13x +15
Therefore, the answer to the question is E) -x2 - 13x +15