1)$\left \{ {{x-6y=17} \atop {5x+y=23}} \right.$
<=> $\left \{ {{5x-30y=85} \atop {5x+y=23}} \right.$
<=> $\left \{ {{31y=-62} \atop {5x+y=23}} \right.$
<=> $\left \{ {{y=-2} \atop {x=5}} \right.$
Vậy (x;y) = (5;-2)
2)$\left \{ {{4x+3y=26} \atop {5x-y=11}} \right.$
<=> $\left \{ {{4x+3y=26} \atop {15x-3y=33}} \right.$
<=> $\left \{ {{19x=59} \atop {4x+3y=26}} \right.$
<=> $\left \{ {{x=\frac{59}{19}} \atop {y=\frac{86}{19}}} \right.$
Vậy (x;y) = ($ \frac{59}{19} ; \frac{86}{19} $)
