已知x、y满足(x-1)(x-1)+|y+2|=0,求代数值2xy(3/4x²-1/2y²)-6xy(1/2x²-1/6y²)的值你们的答案怎么不一样啊
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![已知x、y满足(x-1)(x-1)+|y+2|=0,求代数值2xy(3/4x²-1/2y²)-6xy(1/2x²-1/6y²)的值你们的答案怎么不一样啊](/uploads/image/z/7258423-31-3.jpg?t=%E5%B7%B2%E7%9F%A5x%E3%80%81y%E6%BB%A1%E8%B6%B3%28x-1%29%28x-1%29%2B%7Cy%2B2%7C%3D0%2C%E6%B1%82%E4%BB%A3%E6%95%B0%E5%80%BC2xy%283%2F4x%26%23178%3B-1%2F2y%26%23178%3B%29-6xy%281%2F2x%26%23178%3B-1%2F6y%26%23178%3B%29%E7%9A%84%E5%80%BC%E4%BD%A0%E4%BB%AC%E7%9A%84%E7%AD%94%E6%A1%88%E6%80%8E%E4%B9%88%E4%B8%8D%E4%B8%80%E6%A0%B7%E5%95%8A)
已知x、y满足(x-1)(x-1)+|y+2|=0,求代数值2xy(3/4x²-1/2y²)-6xy(1/2x²-1/6y²)的值你们的答案怎么不一样啊
已知x、y满足(x-1)(x-1)+|y+2|=0,求代数值2xy(3/4x²-1/2y²)-6xy(1/2x²-1/6y²)的值
你们的答案怎么不一样啊
已知x、y满足(x-1)(x-1)+|y+2|=0,求代数值2xy(3/4x²-1/2y²)-6xy(1/2x²-1/6y²)的值你们的答案怎么不一样啊
(x-1)(x-1)+|y+2|=0
x-1=0,y+2=0
x=1,y=-2
2xy(3/4x²-1/2y²)-6xy(1/2x²-1/6y²)
=-3/2x^3y
=3
平方和绝对值都大于等于0,相加等于0,若有一个大于0,则另一个小于0,不成立。
所以两个都等于0
所以x-1=0,y+2=0
x=1,y=-2
原式=3/2x³y-xy³-3x³y+xy³
=-3/2x³y
=6
3
(x-1)(x-1)+|y+2|=0
x-1=0,y+2=0
x=1,y=-2
2xy(3/4x²-1/2y²)-6xy(1/2x²-1/6y²)
=-4乘以(-5/4)+12 乘以(-1/6)
=3
前者在最后一步算错了。
因为(x-1)(x-1)+|y+2|=0,且(x-1)(x-1)大于等于0,|y+2|大于等于0
当且仅当x-1=0,y+2=0
所以x=1,y=-2
代入式2xy(3/4x²-1/2y²)-6xy(1/2x²-1/6y²)
=3
多说一句,是瞎猜的,如果,式子中的x²和y²都是在分母的位置的话,...
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因为(x-1)(x-1)+|y+2|=0,且(x-1)(x-1)大于等于0,|y+2|大于等于0
当且仅当x-1=0,y+2=0
所以x=1,y=-2
代入式2xy(3/4x²-1/2y²)-6xy(1/2x²-1/6y²)
=3
多说一句,是瞎猜的,如果,式子中的x²和y²都是在分母的位置的话,答案仍然等于3,算是一种巧合吧!
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