Question

Решите систему уравнений y-9x=13, 3x+2y=5

Answer 1

$\left \{ {{y-9x=13} \atop {3x+2y=5}} \right.$
$\left \{ {{y=13+9x} \atop {3x+2(13+9x)=5}} \right.$
$\left \{ {{y=13+9x} \atop {3x+26+18x=5}} \right.$
$\left \{ {{y=13+9x} \atop {21x=-21}} \right.$
$\left \{ {{y=13+9x} \atop {x=-1}} \right.$
$\left \{ {{y=13-9} \atop {x=-1}} \right.$
$\left \{ {{y=4} \atop {x=-1}} \right.$
x=-1;y=4