Add or Subtract for #3-4

Question

3. (2x2 + 6x + 1) + (–7x2 + 2x – 3)

5x2 – 4x – 2
–5x2 + 8x – 2
5x2 – 8x + 2
–9x2 – 8x + 2

4. (3x2 – 7x – 4) – (6x2 – 6x + 1)

–3x2 – x –5
–3x2 –13x + 5
9x2 – x + 5
3x2 – 13x – 5

My answers:
3. 5x2 – 8x + 2
4. –3x2 – x –5

Answer 1

#4 is correct, but #3 is not

#3.
(2x2 + 6x + 1) + (–7x2 + 2x – 3)
= 2x^2 + 6x + 1 - 7x^2 + 2x - 3 , the brackets were not needed because a +1 was understood in front of them
= -5x^2 + 8x -2