Составим систему
\left \{ {{x= \frac{-1+3y}{4} } \atop {3 \frac{-1+3y}{4}+2y-12 =0}} \right. => \left \{ {{x= \frac{-1+3y}{4} } \atop { \frac{-1+3y }{4} +2y-12=0}} \right. " alt=" \left \{ {{4x-3y=-1} \atop {3x+2y=12}} \right. => \left \{ {{x= \frac{-1+3y}{4} } \atop {3 \frac{-1+3y}{4}+2y-12 =0}} \right. => \left \{ {{x= \frac{-1+3y}{4} } \atop { \frac{-1+3y }{4} +2y-12=0}} \right. " align="absmiddle" class="latex-formula">
второе уравнение приводим к общему знаменателю и поучаем
\left \{ {{y=3} \atop {17y=51}} \right. => \left \{ {{x=2} \atop {y=3}} \right. " alt=" \left \{ {{x= \frac{-1+3y}{4} } \atop {x=-3+9y+8y-48}} \right. => \left \{ {{y=3} \atop {17y=51}} \right. => \left \{ {{x=2} \atop {y=3}} \right. " align="absmiddle" class="latex-formula">
вот точка пересечения