X的二次方减二XY加Y二次方=x^2-xy+y^2=(x-y)^2+xy=12+1=13
x^2 - 2xy + y^2 x^2 X的二次方= (x - y)^2= [(√3 +√2) - (√3 -√2)]^2= (2√2)^2= 8
8
