(1/2x+1/3y)²-(1/2x-1/3y）²

(1/2x+1/3y)²-(1/2x-1/3y）²
(1/2x+1/3y)²-(1/2x-1/3y）²

(1/2x+1/3y)²-(1/2x-1/3y）²
(1/2x+1/3y)²-(1/2x-1/3y）²
=(1/2x+1/3y+1/2x-1/3y)(1/2x+1/3y-1/2x+1/3y)
=x*2/3y
=2/3xy
如果本题有什么不明白可以追问,