已知x/3=y/4,求7x²-y²/x²-2xy+3y²的值.
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![已知x/3=y/4,求7x²-y²/x²-2xy+3y²的值.](/uploads/image/z/2494197-45-7.jpg?t=%E5%B7%B2%E7%9F%A5x%2F3%3Dy%2F4%2C%E6%B1%827x%26%23178%3B-y%26%23178%3B%2Fx%26%23178%3B-2xy%2B3y%26%23178%3B%E7%9A%84%E5%80%BC.)
已知x/3=y/4,求7x²-y²/x²-2xy+3y²的值.
已知x/3=y/4,求7x²-y²/x²-2xy+3y²的值.
已知x/3=y/4,求7x²-y²/x²-2xy+3y²的值.
设x/3=y/4=k得:x=3k,y=4k
所以7x²-y²/x²-2xy+3y²=(7*9k^2-16k^2)/(9k^2-2*3*4k^2+3*16k^2)=47/33