6. When you add x² + 3x + 4 and x² - 8x, their sum is
a. -x²+ 8x + 2
b. 2x² - 5x + 4
c. 2x² + 2x + 2
d. -2x² - 2x - 10

7. Subtract 3x – 5 by 2x + 6.
a. 5x + 1
b. x - 11
c. x + 1
d. 5x - 11

8. Find the sum of 3x2 - 11x + 12 and 20x - 100.
a. 21x2 - 31x + 88
c. 21x2 - 9x + 88
b. -15x2 - 31x + 112
d. 3x2 + 9x - 88

9. When 3x + 4 is added to -8x - 10, their sum is
a. -5x + 2
b. 8x + 2
c. 2x + 2
d. -5x - 6​