(5x^2+4x-11)-(-x^2-3x-10)+(2-7x-6x^2) 把括号都拆开
=5x^2+4x-11+x^2+3x+10+2-7x-6x^2 合并同类项
=(5+1-6)x^2+(4+3-7)x+(-11+10+2)
=1