已知：x=根号3+1,y=根号3-1,求下列各式的值.

x=√3+1 ,y=√3-1x²+2xy+y²=(x+y)²=(√3+1+√3-1)²=(2√3)²=12x²-y²=(x+y)(x-y)=(√3+1+√3-1)(√3+1-√3+1)=2√3×2=4√3