6x-7y+3与-11x+5y-7的和要加上多少才会等于8x-6y+11?

6x-7y+3与-11x+5y-7的和要加上多少才会等于8x-6y+11?
6x-7y+3与-11x+5y-7的和要加上多少才会等于8x-6y+11?

6x-7y+3与-11x+5y-7的和要加上多少才会等于8x-6y+11?
6x-7y+3与-11x+5y-7的和
=（6x-11x)+(5y-7y)+3-7
=-5x-2y-4
8x-6y+11-(-5x-2y-4)
=13x-4y+15
所以6x-7y+3与-11x+5y-7的和要加上13x-4y+15
才会等于8x-6y+11

答案是：13x-4y+15