Question

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

Answer 1

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

Step-by-step 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