(1)-(x-y-z)= -x+y+z
(2)-[-(a+b)]= a+b
(3)2(3x-2y)-3(2x-3y)= 5y
(4)已知A=2x²+5x,B=x²-11x+6,则A+B= 3x²- 6x+6
5)a²-3a+8 -3a²+5a-7=-2a²+2a+1.
(6)一个多项式减去-2x-1等于6x²+3x-9,则这个多项式是 6x²+5x- 10
(1)-(x-y-z)= -x+y+z
(2)-[-(a+b)]= a+b
(3)2(3x-2y)-3(2x-3y)= 5y
(4)已知A=2x²+5x,B=x²-11x+6,则A+B= 3x²- 6x+6
5)a²-3a+8 -3a²+5a-7=-2a²+2a+1.
(6)一个多项式减去-2x-1等于6x²+3x-9,则这个多项式是 6x²+5x- 10