已知2x-3y=0,求(2x^2-3y^2)/(3x^2-2xy)的值

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已知2x-3y=0,求(2x^2-3y^2)/(3x^2-2xy)的值已知2x-3y=0,求(2x^2-3y^2)/(3x^2-2xy)的值已知2x-3y=0,求(2x^2-3y^2)/(3x^2-2

已知2x-3y=0,求(2x^2-3y^2)/(3x^2-2xy)的值
已知2x-3y=0,求(2x^2-3y^2)/(3x^2-2xy)的值

已知2x-3y=0,求(2x^2-3y^2)/(3x^2-2xy)的值
解由2x-3y=0,
即2x=3y
得x=3/2y
即(2x^2-3y^2)/(3x^2-2xy)
=[2(3/2y)^2-3y^2]/[3(3/2y)^2-3y*y]
=[9/2y^2-3y^2]/[27/4y^2-3y²]
=[3/2y^2]/[15/4y^2]
=(3/2)/(15/4)
=3/2*4/15
=2/5

解由2x-3y=0,
即2x=3y
得x=3/2y
即(2x^2-3y^2)/(3x^2-2xy)
=[2(3/2y)^2-3y^2]/[3(3/2y)^2-3y*y]
=[9/2y^2-3y^2]/[27/4y^2-3y²]
=[3/2y^2]/[15/4y^2]
=(3/2)/(15/4)
=3/2*4/15
=2/5