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
ni da gong shi,bu yao dong,
jiu zhan zai na!
qian wan bu yao shuo hua a!
ni zhi neng reng xue qiu zhi lei.
bian ren de ni shi yi xia ba!
hao you dou ke yi dong,bai bao xiang jiu shi peng peng yun qi lo!
huo zhe quan bu xing jiu cong shang.