已知x/y=3,求2x²-3xy+5y²/x²+3xy-y²的值
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![已知x/y=3,求2x²-3xy+5y²/x²+3xy-y²的值](/uploads/image/z/2713553-17-3.jpg?t=%E5%B7%B2%E7%9F%A5x%2Fy%3D3%2C%E6%B1%822x%26%23178%3B-3xy%2B5y%26%23178%3B%2Fx%26%23178%3B%2B3xy-y%26%23178%3B%E7%9A%84%E5%80%BC)
已知x/y=3,求2x²-3xy+5y²/x²+3xy-y²的值
已知x/y=3,求2x²-3xy+5y²/x²+3xy-y²的值
已知x/y=3,求2x²-3xy+5y²/x²+3xy-y²的值
x/y=3,则
x=3y,于是
(2x²-3xy+5y²)/(x²+3xy-y²)
=(2*9y²-3y*3y+5y²)/(9y²+3y*3y-y²)
=(18y²-9y²+5y²)/(9y²+9y²-y²)
=(14y²)/(17y²)
=14/17