Решите систему уравнений: х +3у =19 3х +7у = 49 Решите систему уравнений: х +3у =19 3х +7у = 49 помагите пж, с решением!

[latex] \left \{ {{x=19-3y} \atop {3*(19-3y)+7y=49}} \right. [/latex] [latex] \left \{ {{x=19-3y} \atop {2y=57-49}} \right. [/latex] [latex] \left \{ {{x=19-3y} \atop {y=4}} \right. [/latex] [latex] \left \{ {{x=19-3*4} \atop {y=4}} \right. [/latex] [latex] \left \{ {{y=4} \atop {x=7}} \right. [/latex] [latex] \left \{ {{2y=19-3x} \atop {4x+5y=37}} \right. [/latex]  [latex] \left \{ {{y=9,5-1,5x} \atop {4x+5(9,5-1,5x)=37}} \right. [/latex]  [latex] \left \{ {{y=9,5-1,5x} \atop {3,5x=47,5-37}} \right. [/latex]  [latex] \left \{ {{x=3} \atop {y=9,5-1,5*3}} \right. [/latex]  [latex] \left \{ {{x=3} \atop {y=5}} \right. [/latex]