[tex] \frac{x-3y}{2x+7y} = \frac{6}{90} [/tex]
<=> 90(x-3y)=6(2x+7y)
<=> 90x -270y= 12x+42y
<=>78x=312y
<=>[tex] \frac{312}{72} = \frac{x}{y} \ \textless \ =\ \textgreater \ \frac{156}{36} = \frac{x}{y} [/tex]
[tex] \frac{78}{18} = \frac{x}{y} \ \textless \ =\ \textgreater \ \frac{39}{9} = \frac{x}{y} [/tex]