Question

РЕШИТЕ МЕТОДОМ ПОДСТАНОВКИ СИСТЕМУ УРАВНЕНИЙ, ПОЖАЛУЦСТА!!!!

Answer 1

$\left \{ {{3x+4y=-2} \atop {6x-7y=11}} \right. \left \{ {{x=- \frac{2}{3}- \frac{4}{3}y } \atop {6x-7y=11}} \right. \\ \\6(- \frac{2}{3}- \frac{4}{3}y)-7y=11\\ \\-4-8y-7y=11 \\-4-15y=11 \\-15y=11+4 \\-15y=15 \\y=-1\\ \\ x=- \frac{2}{3} - \frac{4}{3}*(-1)\\ \\ x=- \frac{2}{3}+ \frac{4}{3}*1\\ \\x=- \frac{2}{3} + \frac{4}{3}\\ \\x= \frac{2}{3}\\ \\(x.y)=( \frac{2}{3}.-1)$