Question

решить систему уравнений:

2x+5=1-x+2y

14x-5=9x-3y-2

Answer 1

$left { {{2x+5=1-x+2y} atop {14x-5=9x-3y-2}} right. \ \ left { {{2x +x -2y=1-5} atop {14x-9x+3y=-2+5}} right. \ \ left { {{3x-2y=-4} atop {5x+3y=3}} right.$

умножим верх на 3 , а низ на 2 и суммуем.

$left { {{9x-6y=-12} atop {10x+6y=6}} right. \ \ 19x=-6 \ x = -frac{6}{19}\ \ 3 *(-frac{6}{19}) - 2 y = -4\ \ -frac{18}{19} - 2y = -4\ \ -2y = -4 + frac{18}{19}\ \ -2y = -frac{58}{19}\ \ y = frac{29}{19}$