若x/y=2,求7x²-3xy+2y²/2x²-3xy+7y²的值 答案是8/3

若x/y=2,求7x²-3xy+2y²/2x²-3xy+7y²的值 答案是8/3
若x/y=2,求7x²-3xy+2y²/2x²-3xy+7y²的值 答案是8/3

若x/y=2,求7x²-3xy+2y²/2x²-3xy+7y²的值 答案是8/3
x=2y
则x²=4y²
xy=2y²
所以原式=(28y²-6y²+2y²)/(8y²-6y²+7y²)
=24y²/9y²
=8/3