已知(x+y)²=25,xy=6,求x-y的值
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已知(x+y)²=25,xy=6,求x-y的值
已知(x+y)²=25,xy=6,求x-y的值
已知(x+y)²=25,xy=6,求x-y的值
(x-y)²=﹙x+y)²-4xy=25-24=1
x-y=±1
(x-y)²
=(x+y)²-4xy
=25-24
=1
x-y=±1
(x-y)²
=(x+y)²-4xy
=25-4*6
=1
x-y=±1
+1或者-1
(x-y)²=(x+y)²-4xy=25-24=1
x-y=±1