(根号x+根号y)²/(根号x+根号y)=(根号x+根号y)
(x+2根号xy+y)除以(根号x+根号y)=(根号x+根号y)²/(根号x+根号y)=根号x+根号y
(x+2根号xy+y)除以(根号x+根号y)=(根号x+根号y)2/(根号x+根号y)=根号x+根号y
=(√x+√y)²/(√x+√y)=√x+√y
