x+y=√5
y-x=√2
xy=3/4
1)
x^2+2xy+y^2
=(x+y)^2
=(√5)^2
=5
2）
y/x-x/y
=(y^2-x^2)/xy
=(y+x)(y-x)/xy
=√5*√2/(3/4)
=4√10/3