Решите систему уравнения 5х+7у=2; 2х-7у=23

Ответ:

$(3\frac{4}{7}; -2\frac{13}{49})$

Объяснение:

$\left \{ {{5x+7y=2} \atop {2x-7y=23}} \right.\\\\ +\left \{ {{5x+7y=2} \atop {2x-7y=23}} \right.\\\\7x = 25\\\\x = \frac{25}{7}\\\\2\cdot \frac{25}{7} - 7y = 23 \\\\ \frac{50}{7} - 7y = 23|\cdot7\\\\50 - 49y = 161\\\\49y = 50 - 161\\\\49y = -111\\\\y = -\frac{111}{49} = -2\frac{13}{49}$