x-5y=23;

7x+10y=-19;

-

x=23+5y;

7(23+5y)+10y=-19;

-

x=23+5y;

161+35y+10y=-19;

-

x=23+5y;

45y=-180;

-

x=23+5y;

y=-4;

-

x=23+5*(-4);

y=-4;

-

x=3;

y=-4.