问题 解答题
计算
(1)(
1
3
a2b3)•(-15a2b2
(2)(
1
2
x2y-2xy+y2)•2xy
(3)(2x+3)(3x+4)
(4)(3x+7y)(3x-7y)
(5)(x-3y)2
(6)(x+5y)2
答案

(1)(

1
3
a2b3)•(-15a2b2)=-5a4b5

(2)(

1
2
x2y-2xy+y2)•2xy=x3y2-4x2y2+2xy3

(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

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