Срочно! Решите систему уравнений: 2х+у=20 х-3у=-1 А вторая система уравнений 9х+13у=31 18х-5у=31

[latex]1)[/latex] [latex] \left \{ {{2x+y=20} \atop {x-3y=-1}} \right. [/latex] [latex] \left \{ {{6x+3y=60} \atop {y=20-2x}} \right. [/latex] [latex] \left \{ {{7x=59} \atop {y=20-2x}} \right. [/latex] [latex] \left \{ {{x=8 \frac{3}{7} } \atop {y=20-2*8 \frac{3}{7} }} \right. [/latex] [latex]\left \{ {{x=8 \frac{3}{7} } \atop {y=20-16 \frac{6}{7} }} \right. [/latex] [latex]\left \{ {{x=8 \frac{3}{7} } \atop {y=3 \frac{1}{7} }} \right. [/latex] Ответ: [latex](8 \frac{3}{7};3 \frac{1}{7}) [/latex] [latex]2)[/latex] [latex] \left \{ {{9x+13y=31} \atop {18x-5y=31}} \right. [/latex] [latex] \left \{ {{-18x-26y=-62} \atop {18x-5y=31}} \right. [/latex] [latex] \left \{ {{-31y=-31} \atop {9x=31-13y}} \right. [/latex] [latex] \left \{ {{y=1} \atop {9x=31-13*1}} \right. [/latex] [latex]\left \{ {{y=1} \atop {9x=18}} \right. [/latex] [latex]\left \{ {{y=1} \atop {x=2}} \right. [/latex] Ответ: [latex](2;1)[/latex]