问题:
计算.
(1)(x-1)(x 2+x+1);
(2)-5x(-x 2+2x+1)-(2x+3)(5-x 2);
(3)(3x-y)(y+3x)-(x-3y)(4x+3y).
计算.
(1)(x-1)(x 2+x+1);
(2)-5x(-x 2+2x+1)-(2x+3)(5-x 2);
(3)(3x-y)(y+3x)-(x-3y)(4x+3y).
(1)(x-1)(x 2+x+1);
(2)-5x(-x 2+2x+1)-(2x+3)(5-x 2);
(3)(3x-y)(y+3x)-(x-3y)(4x+3y).
参考答案: