x^2+y^2=25,x-y=1,求xy的值
问题描述:
x^2+y^2=25,x-y=1,求xy的值
答
x^2+y^2=25,x-y=1,(x-y)^2=1 x^2+y^2-2xy=1 25-2xy=1 2xy=24 xy=12
x^2+y^2=25,x-y=1,求xy的值
x^2+y^2=25,x-y=1,(x-y)^2=1 x^2+y^2-2xy=1 25-2xy=1 2xy=24 xy=12