Question

x-2y=-10 7x-10y=7 решить систему уравнений методом постановки. Система двух линейных уравнений ( распределительный закон умножения

Answer 1

$\displaystyle\bf\\\left \{ {{x-2y=-10} \atop {7x-10y=7}} \right.\\\\\\\left \{ {{x=2y-10} \atop {7\cdot(2y-10)-10y=7}} \right. \\\\\\\left \{ {{x=2y-10} \atop {14y-70-10y=7}} \right. \\\\\\\left \{ {{x=2y-10} \atop {4y=77}} \right.\\\\\\\left \{ {{x=2\cdot 19,25-10\cdot} \atop {y=19,25}} \right. \\\\\\\left \{ {{x=38,5-10} \atop {y=19,25}} \right. \\\\\\\left \{ {{x=28,5} \atop {y=19,25}} \right.\\\\\\Otvet \ : \ \Big(28,5 \ \ ; \ \ 19,25\Big)$