计算:①[(2x-3y)2]3(3y-2x)3(3y-2x)4(结果用幂的形式表示)②(x-3y)(x+3y)-(x-3y)2③97×103+99×99④(x-2)(x+2)(x2+4)⑤(2x+y-

题目简介

计算:①[(2x-3y)2]3(3y-2x)3(3y-2x)4(结果用幂的形式表示)②(x-3y)(x+3y)-(x-3y)2③97×103+99×99④(x-2)(x+2)(x2+4)⑤(2x+y-

题目详情

计算:
①[(2x-3y)2]3(3y-2x)3(3y-2x)4(结果用幂的形式表示)
②(x-3y)(x+3y)-(x-3y)2
③97×103+99×99
④(x-2)(x+2)(x2+4)
⑤(2x+y-3z)(2x-y+3z)
⑥(3x-2y)2-3(3x-y)(3x+y)
⑦(2m-3n)(2m+3n)(4m2-9n2
题型:解答题难度:中档来源:不详

答案

①[(2x-3y)2]3(3y-2x)3(3y-2x)4(结果用幂的形式表示)
=(2x-3y)6(3y-2x)7
=(3y-2x)6(3y-2x)7
=(3y-2x)13;

②(x-3y)(x+3y)-(x-3y)2
=x2-(3y)2-(x2-6xy+9y2)
=x2-9y2-x2+6xy-9y2
=-18y2+6xy;

③97×103+99×99
=(100-3)(100+3)+(100-1)2
=1002-9+10000+1-200
=10000-9+10000+1-200
=19792;

④(x-2)(x+2)(x2+4)
=(x2-4)(x2+4)
=x4-16;

⑤(2x+y-3z)(2x-y+3z)
=[2x+(y-3z)][2x-(y-3z)]
=(2x)2-(y-3z)2
=4x2-(y2-6yz+9z2)
=4x2-y2+6yz-9z2;

⑥(3x-2y)2-3(3x-y)(3x+y)
=9x2-12x+4y2-3(9x2-y2)
=9x2-12x+4y2-27x2+3y2
=-18x2+7y2-12x;

⑦(2m-3n)(2m+3n)(4m2-9n2)
=(4m2+9n2)(4m2-9n2)
=16m4-81n4.

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