\left \{ {{3x - 4 = 2y - 5} \atop {3y - 9 = x + 3}} \right.
\left \{ {{3x-2y=- 5+4} \atop {x=3y-9-3}} \right.
\left \{ {{3x-2y=-1} \atop {x=3y-12}} \right.
\left \{ {{3(3y-12)-2y=-1} \atop {x=3y-12}} \right.
\left \{ {{9y-36-2y=-1} \atop {x=3y-12}} \right.
\left \{ {{7y=-1+36} \atop {x=3y-12}} \right.
\left \{ {{7y=35} \atop {x=3y-12}} \right.
\left \{ {{y=5} \atop {x=3*5-12}} \right.
\left \{ {{y=5} \atop {x=15-12}} \right.
\left \{ {{y=5} \atop {x=3}} \right.
…
\left \{ {{x + y + 1 = 5x - 4y} \atop {x = y + 1}} \right.
\left \{ {{y + 1 + y + 1 = 5(y + 1) - 4y} \atop {x = y + 1}} \right.
\left \{ {{2y + 2= 5y + 5 - 4y} \atop {x = y + 1}} \right.
\left \{ {{2y + 2= y + 5 } \atop {x = y + 1}} \right.
\left \{ {{2y-y=5-2 } \atop {x = y + 1}} \right.
\left \{ {{y=3 } \atop {x = 3 + 1}} \right.
\left \{ {{y=3 } \atop {x =4}} \right.