3x+2y-75=3 ,3x=78-2y ,x=26-2y/3;
x/3-y/4=3 ,4x-3y=36 ,4x=36+3y ,x=9+3y/4;
x=26-2y/3=9+3y/4
2y/3+3y/4=17 17y/12=17 y=12
x=26-2y/3=18