Question

можете помочь
Тема:Решение систем линейных уравнений
срочно!!!!
пример а)​

Answer 1

$\displaystyle\bf\\\left \{ {{\dfrac{y}{4} -\dfrac{x}{5} =6} \atop {\dfrac{x}{15} +\dfrac{y}{12} =0}} \right. \\\\\\\left \{ {{\dfrac{y}{4} \cdot 20-\dfrac{x}{5} \cdot 20=6\cdot 20} \atop {\dfrac{x}{15} \cdot 60+\dfrac{y}{12} \cdot 60=0}} \right. \\\\\\\left \{ {{5y-4x=120} \atop {4x+5y=0}} \right. \\\\\\+\left \{ {{-4x+5y=120} \atop {4x+5y=0}} \right. \\-----------\\10y=120\\\\y=12\\\\4x=-5y=-5\cdot 12=-60\\\\x=-60:4=-15\\\\\\Otvet \ : \ (-15 \ ; \ 12)$