Question

若x+y=2,xy=-1/2,则x的平方+y的平方=?,x-y=?

初二的，详细过程，谢谢！

Answer 1

x^2+y^2=(x+y)^2-2xy=5
x^2+y^2=(x-y)^2+2xy=5
=(x-y)^2=6
=x-y=正负根号6

Answer 2

x^2+y^2=(x+y)^2-2xy=5
x^2+y^2=(x-y)^2+2xy=5
=(x-y)^2=6
=x-y=根号6

Answer 3

1)x方+y方＝(y+x)方-2xy=4+1=5(2)（x-y）方=x方+y方-2xy=5所以x-y=正负根5