Question

 

$left { {{5a-3b=11} atop {3a+b=1}} right.$

Answer 1

 

$left { {{5a-3b=11,} atop {3a+b=1;}} right. left { {{5a-3b=11,} atop {9a+3b=3;}} right. \ 14a=14, \ a=1; \ left { {{a=1,} atop {3+b=1;}} right. left { {{a=1,} atop {b=-2.}} right. \ (1;-2)$