(2x^2+6x-11)-(5x^2-x+7)
Pretend that there is a -1 in front of the second bracket
-1(5x^2-x+7)=-5x^2+x-7
2x^2+6x-11-5x^2+x-7
2x^2-5x^2+6x+x-11-7 ( combine like terms)\
-3x^2+7x-18
Answer: d. -3x^2+7x-18
