已知x²+2xy+y²\xy-y²÷A=xy+y²\x²-2xy+y²,当x=2,y=1时,求A的值

已知x²+2xy+y²\xy-y²÷A=xy+y²\x²-2xy+y²,当x=2,y=1时,求A的值
已知x²+2xy+y²\xy-y²÷A=xy+y²\x²-2xy+y²,当x=2,y=1时,求A的值

已知x²+2xy+y²\xy-y²÷A=xy+y²\x²-2xy+y²,当x=2,y=1时,求A的值
代入
(4十4十1)/(2-1/A)=(2十1)/(4-4十1)
5/2-5A=3
5A=-1/2
A=-1/10