问题 解答题

计算:

(1)6a5b6c4÷(-3a2b3c)÷(2a3b3c3).

(2)(x-4y)(2x+3y)-(x+2y)(x-y).

(3)[(-2x2y)2]3•3xy4

(4)(m-n)(m+n)+(m+n)2-2m2

答案

(1)原式=-2a3b3c3÷(2a3b3c3)=-1;

(2)原式=2x2-5xy-12y2-x2-xy+2y2=x2-6xy-10y2

(3)原式=64x12y6•3xy4=192x13y10

(4)原式=m2-n2+m2+2mn+n2-2m2=2mn.

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