初一4道计算题(1).(-1/2x+2y)^2(2).4(-3/2x-3y)(3/2x-3y)(3).x^2-(x+2)

初一4道计算题
(1).(-1/2x+2y)^2
(2).4(-3/2x-3y)(3/2x-3y)
(3).x^2-(x+2)(x-2)
(4).(x/2+5)^2-(x/2-5)^2
yuhao1600 1年前 已收到4个回答 举报
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炫酷之族 幼苗

共回答了18个问题采纳率：88.9% 举报

(1).(-1/2x+2y)^2
＝1/4x^2-xy+4y^2
(2).4(-3/2x-3y)(3/2x-3y)
=-9x^2+36xy+36Y^2
(3).x^2-(x+2)(x-2)
=x^2-x^2+4
=4
(4).(x/2+5)^2-(x/2-5)^2
=(x/2+5+x/2-5)(x/2+5-x/2+5)
=10x

1年前

5

keleyu123 幼苗

共回答了2个问题 举报

(1)
=1/4(Y-X)^2
=1/4X^2+1/4Y^2-1/2XY
(2)
=-4(3/2x+3y)(3/2x-3y)
=-4(9/4x^2-9y^2)
=36y^2-9x^2
(3)
=x^2-(x^2-4)
=4
(4)
=[(x/2+5)-(x/2-5)][(x/2+5)+(x/2-5)]
=10x

1年前

2

redbaby1224 幼苗

共回答了2个问题 举报

(1)1/4x^2-2y/x+4y^2
(2)=-4(3/2x+3y)(3/2x-3y)=-4(9/4x^2-9y^2)=-9/x^2+3
6y^2
(3)=x^2-(x^2-4)=x^2-x^2+4=4
(4)=x^2/4+5x+25-x^2/4+5x-25=10x

1年前

1

学会孤寂 幼苗

共回答了63个问题 举报

(1).(-1/2x+2y)^2
＝(4xy-1)^2
=16x^2y^2-8xy+1
(2).4(-3/2x-3y)(3/2x-3y)
=-4(3/2x+3y)(3/2x-3y)
=-4[(3/2x)^2-(3y)^2]
=36y^2-9x^2
(3).x^2-(x+2)(x-2)
=x^2-(x^2-4)
=4
(4).(x/2+5)^2-(x/2-5)^2
=(x/2+5+x/2-5)(x/2+5-x/2+5)
=10x

1年前

1
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