Question

4x + 3y = -15 5x + 3y = -3.​

Answer 1

$\displaystyle\bf\\\left \{ {{4x+3y=-15} \ |\cdot(-1) \atop {5x+3y=-3}} \right. \\\\\\+\left \{ {{-4x-3y=15} \atop {5x+3y=-3}} \right. \\----------\\x=12\\\\3y=-5x-3=-5\cdot 12-3=-60-3=-63\\\\y=-63:3=-21\\\\Otvet \ : \ (12 \ ; \ -21)$