Question

3: ( 3x - y = 7, (2x + 3y = 1.​

Answer 1

$\displaystyle\bf\\\left \{ {{3x - y = 7 \: \: | \times 3} \atop {2x + 3y = 1 }} \right. \\ \displaystyle\bf\\ + \left \{ {{9x - 3y = 21} \atop {2x + 3y = 1 }} \right. \\ \\ 9x + 2x = 21 + 1 \\ 11x = 22 \\ x =22 \div 11 \\ x = 2 \\ \\ 3 \times 2 - y = 7 \\ 6 - y = 7 \\ y = 6 - 7 \\ y = - 1$

Ответ: ( 2 ; - 1 )