1.(x-2y)(2y-x)=2.(a-b)^2=_____=(a+b)^23.x-1/X=5,则x^2+1/x^2=____4.若a(a-1)-(a^2-b)=4,则(a^2+b^2)/2-ab的值是——5.已知x-y=7,xy=60,求x^2+y^2及(x+y)^2的值最主要第五题
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![1.(x-2y)(2y-x)=2.(a-b)^2=_____=(a+b)^23.x-1/X=5,则x^2+1/x^2=____4.若a(a-1)-(a^2-b)=4,则(a^2+b^2)/2-ab的值是——5.已知x-y=7,xy=60,求x^2+y^2及(x+y)^2的值最主要第五题](/uploads/image/z/4356082-10-2.jpg?t=1.%28x-2y%29%EF%BC%882y-x%29%3D2.%28a-b%29%5E2%3D_____%3D%28a%2Bb%29%5E23.x-1%2FX%3D5%2C%E5%88%99x%5E2%2B1%2Fx%5E2%3D____4.%E8%8B%A5a%28a-1%29-%28a%5E2-b%29%3D4%2C%E5%88%99%28a%5E2%2Bb%5E2%29%2F2-ab%E7%9A%84%E5%80%BC%E6%98%AF%E2%80%94%E2%80%945.%E5%B7%B2%E7%9F%A5x-y%3D7%2Cxy%3D60%2C%E6%B1%82x%5E2%2By%5E2%E5%8F%8A%EF%BC%88x%2By%29%5E2%E7%9A%84%E5%80%BC%E6%9C%80%E4%B8%BB%E8%A6%81%E7%AC%AC%E4%BA%94%E9%A2%98)
1.(x-2y)(2y-x)=2.(a-b)^2=_____=(a+b)^23.x-1/X=5,则x^2+1/x^2=____4.若a(a-1)-(a^2-b)=4,则(a^2+b^2)/2-ab的值是——5.已知x-y=7,xy=60,求x^2+y^2及(x+y)^2的值最主要第五题
1.(x-2y)(2y-x)=
2.(a-b)^2=_____=(a+b)^2
3.x-1/X=5,则x^2+1/x^2=____
4.若a(a-1)-(a^2-b)=4,则(a^2+b^2)/2-ab的值是——
5.已知x-y=7,xy=60,求x^2+y^2及(x+y)^2的值
最主要第五题
1.(x-2y)(2y-x)=2.(a-b)^2=_____=(a+b)^23.x-1/X=5,则x^2+1/x^2=____4.若a(a-1)-(a^2-b)=4,则(a^2+b^2)/2-ab的值是——5.已知x-y=7,xy=60,求x^2+y^2及(x+y)^2的值最主要第五题
⒈原式=(x-2y)[-(x-2y)]=-(x-2y)²=-x²+4xy-4y²
⒉(a-b)²=(a-b)²+4ab=(a+b)²
⒊两边平方:(x-1/x)²=x²-2×x×(1/x)+1/x²=x²+1/x²-2=25
则x²+1/x²=27
⒋a(a-1)-(a²-b)=a²-a-a²+b=b-a=4
两边平方:(b-a)²=b²+a²-2ab=16
∴a²+b²=16+2ab
∴原式=(16+2ab)/2-ab=8+ab-ab=8
⒌x²+y²=x²-2xy+y²+2xy=(x-y)²+2xy=7²+2×60=49+120=169
(x+y)²=x²-2xy+y²+4xy=(x-y)²+4xy=7²+4×60=49+240=289
(5) x²+y²=(x-y)²+2xy=7²+2×60=169 (x+y)²=(x-y)²+4xy=7²+4×60=289
(x-2y)(2y-x)=-x^2+4xy-4y^2
2.(a-b)^2=_a^2-2ab+b^2 (a+b)^2=a^2+2ab+b^2
3.x-1/X=5,则x^2+1/x^2=__27__ &nbs...
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(x-2y)(2y-x)=-x^2+4xy-4y^2 x²+y²=(x-y)²+2xy=7²+2×60=169 (x+y)²=(x-y)²+4xy=7²+4×60=289
2.(a-b)^2=_a^2-2ab+b^2 (a+b)^2=a^2+2ab+b^2
3.x-1/X=5,则x^2+1/x^2=__27__ ! (x-1/x)^2=x^2+(1/x)^2-2=25
4.若a(a-1)-(a^2-b)=4,则(a^2+b^2)/2-ab的值是——
5.已知x-y=7,xy=60,求x^2+y^2及(x+y)^2的值
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