求x-y的值和求x^y的值
(1)x^2+y^2-2xy-6x+6y+9=0,
(2)x^2+y^2+13=6x-4y,求x^y的值
(1)x^2+y^2-2xy-6x+6y+9=0,
(x-y)^2-6(x-y)+9=0
[(x-y)-3]^2=0
(x-y)-3=0
x-y=3
(2)x^2+y^2+13=6x-4y,求x^y的值
x^2-6x+9+y^2+4y+4=0
(x-3)^2+(y+2)^2=0
x-3=0, x=3
y+2=0, y=-2
x^y=3^(-2)=1/9
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