x和y均为正数,若x-y=2,xy=8,求x+y的值

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x和y均为正数,若x-y=2,xy=8,求x+y的值

x和y均为正数,若x-y=2,xy=8,求x+y的值
x和y均为正数,若x-y=2,xy=8,求x+y的值

x和y均为正数,若x-y=2,xy=8,求x+y的值
(x-y)^2=x^2-2xy+y^2=x^2+2xy+y^2-4xy=(x+y)^2-4xy=4
(x+y)^2=4+4xy=4+32=36
x+y=6或-6