问题
解答题
计算 (1)(
(2)(
(3)(2x+3)(3x+4) (4)(3x+7y)(3x-7y) (5)(x-3y)2 (6)(x+5y)2 |
答案
(1)(
a2b3)•(-15a2b2)=-5a4b5;1 3
(2)(
x2y-2xy+y2)•2xy=x3y2-4x2y2+2xy3;1 2
(3)(2x+3)(3x+4),
=6x2+8x+9x+12,
=6x2+17x+12;
(4)(3x+7y)(3x-7y)=9x2-47y2;
(5)(x-3y)2=x2-6xy+9y2;
(6)(x+5y)2式=x2+10xy+25y2.