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计算题,1.5a^2b/(-1/3ab)*2ab^22.[(x+2y)^2-(x+y)(x-y)-5y^2]/2x3.(2a-b+3)(2a-3+b)
题目详情
计算题,
1.5a^2b/(-1/3ab)*2ab^2
2.[(x+2y)^2-(x+y)(x-y)-5y^2]/2x
3.(2a-b+3)(2a-3+b)
1.5a^2b/(-1/3ab)*2ab^2
2.[(x+2y)^2-(x+y)(x-y)-5y^2]/2x
3.(2a-b+3)(2a-3+b)
▼优质解答
答案和解析
1.5a^2b/(-1/3ab)*2ab^2
=-15a*2ab^2
=-30a^2b^2
2.[(x+2y)^2-(x+y)(x-y)-5y^2]/2x
=[x^2+4xy+4y^2-(x^2-y^2)-5y^2]/2x
=(x^2+4xy+4y^2-x^2+y^2-5y^2)/2x
=4xy/2x
=2y
3.(2a-b+3)(2a-3+b)
=[2a+(3-b)][2a-(3-b)]
=(2a)^2-(3-b)^2
=4a^2-(9-6b+b^2)
=4a^2-9+6b-b^2
=-15a*2ab^2
=-30a^2b^2
2.[(x+2y)^2-(x+y)(x-y)-5y^2]/2x
=[x^2+4xy+4y^2-(x^2-y^2)-5y^2]/2x
=(x^2+4xy+4y^2-x^2+y^2-5y^2)/2x
=4xy/2x
=2y
3.(2a-b+3)(2a-3+b)
=[2a+(3-b)][2a-(3-b)]
=(2a)^2-(3-b)^2
=4a^2-(9-6b+b^2)
=4a^2-9+6b-b^2
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