如果x/3y=y/(2x-5y)=(6x-15y)/xx/3y=y/(2x-5y)=(6x-15y)/x 求(4x^2-5xy+6y^2)/(x^2-2xy+3y^2)=?
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![如果x/3y=y/(2x-5y)=(6x-15y)/xx/3y=y/(2x-5y)=(6x-15y)/x 求(4x^2-5xy+6y^2)/(x^2-2xy+3y^2)=?](/uploads/image/z/2548921-49-1.jpg?t=%E5%A6%82%E6%9E%9Cx%2F3y%3Dy%2F%282x-5y%29%3D%286x-15y%29%2Fxx%2F3y%3Dy%2F%282x-5y%29%3D%286x-15y%29%2Fx+%E6%B1%82%284x%5E2-5xy%2B6y%5E2%29%2F%28x%5E2-2xy%2B3y%5E2%29%3D%3F)
如果x/3y=y/(2x-5y)=(6x-15y)/xx/3y=y/(2x-5y)=(6x-15y)/x 求(4x^2-5xy+6y^2)/(x^2-2xy+3y^2)=?
如果x/3y=y/(2x-5y)=(6x-15y)/x
x/3y=y/(2x-5y)=(6x-15y)/x 求(4x^2-5xy+6y^2)/(x^2-2xy+3y^2)=?
如果x/3y=y/(2x-5y)=(6x-15y)/xx/3y=y/(2x-5y)=(6x-15y)/x 求(4x^2-5xy+6y^2)/(x^2-2xy+3y^2)=?
x/3y=y/2x-5y
2x^2-5xy-3y^2=0
(x-3y)(2x+y)=0①
x/3y=6x-15y/x
x^2-18xy+45y^2=0
(x-3y)(x-15y)=0②
y/2x-5y=6x-15y/x
xy=3(2x-5y)^2
(x-3y)(12x-25)=0③
若①②③同时成立,
x-3y=0,x=3y
(4x^2-5xy+6y^2)/(x^2-2xy+3y^2)
=[4(3y)^2-5*(3y)*y+6y^2]/[(3y)^2-2*(3y)*y+3y^2]
=9/2
数学题
xy
2
不会
不知道有没有学过matlab啊 直接编程就行了吧
太复杂了
x/(3y)=y/(2x-5y)=(6x-15y)/x
x/(3y)=y/(2x-5y)--->2x^2-5xy-3y^2=0--->x=-y/2 or 3y--->x/y=-1/2;or 3
x/(3y)=(6x-15y)/x--->x^2-18xy+45y^2=0--->x=3y or 15y--->x/y=3 or 15
y/(2x-5y)=(6x-15y)/x...
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x/(3y)=y/(2x-5y)=(6x-15y)/x
x/(3y)=y/(2x-5y)--->2x^2-5xy-3y^2=0--->x=-y/2 or 3y--->x/y=-1/2;or 3
x/(3y)=(6x-15y)/x--->x^2-18xy+45y^2=0--->x=3y or 15y--->x/y=3 or 15
y/(2x-5y)=(6x-15y)/x--->12x^2-61xy+75y^2=0
--->x=3y;or 25y/12.
因为三个等式同时成立,有且只有x/y=3才成立--->x=3y.代入所求的分式:
(4x^2-5xy+6y^2)/(x^2-2xy+3y^2)
=(36y^2-15y^2+6y^2)/(9y^2-6y^2+3y^2)
=27/6
=9/2.
收起
a