Question

Решите систему уравнений
3х - у = -1
-х + 2у = 7

Answer 1

$left { {{3x-y=-1} atop {-x+2y=7|cdot 3}} right. ; oplus ; left { {{3x-y=-1} atop {5y=20}} right. ; ; left { {{3x=-1+4} atop {y=4}} right. ; ; left { {{x=1} atop {y=4}} right. \\Otvet:; ; (1,4); .$