若x+y=10,xy=24,则x²+y²=?(x-y)²=?
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![若x+y=10,xy=24,则x²+y²=?(x-y)²=?](/uploads/image/z/4517396-44-6.jpg?t=%E8%8B%A5x%2By%3D10%2Cxy%3D24%2C%E5%88%99x%26%23178%3B%2By%26%23178%3B%3D%3F%EF%BC%88x-y%EF%BC%89%26%23178%3B%3D%3F)
若x+y=10,xy=24,则x²+y²=?(x-y)²=?
若x+y=10,xy=24,则x²+y²=?(x-y)²=?
若x+y=10,xy=24,则x²+y²=?(x-y)²=?
将x+y=10平方
得x^2+2xy+y^2=100
减去4xy,
得x^2-2xy+y^2=4
即x-y=2或-2
联立,得
x=6,y=4
或x=4,y=6
则x^2+y^2=52
(X-Y)^2=4