x^2+y^2=16 ,xy=6怎么解
问题描述:
x^2+y^2=16 ,xy=6怎么解
答
(x+y)^2=x^2+y^2+2xy=16+12=28(x-y)^2=x^2+y^2-2xy=16-12=4(x+y)=2√7 x-y=2 x+y=2√7 x-y=-2x=√7+1 y=√7-1 x=√7-1 y=√7+1x+y=-2√7 x-y=2 x+y=-2√7 x-y=-2x=-√7+1 y=-√7-1 x=-√7-1 y=-√7+1