[tex]\displaystyle\bf\\ + \left \{ {{x + y = 3} \atop {x - y = 1 }} \right. \\ \\ x + x = 3 + 1 \\ 2x = 4 \\ x = 4 \div 2 \\ x = 2 \\ \\ 2 + y = 3 \\ y = 3 - 2 \\ y = 1[/tex]

Ответ: в)