Question

Знайлить точку перетину прямих 2x-y+7=0 i x-5y-1=0

Answer 1

$\displaystyle\left \{ {{2x-y+7=0} \atop {x-5y-1=0}} \right.\\\\\\\displaystyle\left \{ {{2x-y=-7} \atop {x-5y=1| \cdot(-2)} \right. \\\\\\+\displaystyle\left \{ {{2x-y=-7} \atop {-2x+10y=-2}} \right. \\----------\\9y=-9\\\\\boxed{y=-1}\\\\x=5y+1=5\cdot(-1)+1=-5+1=-4\\\\\boxed{x=-4}\\\\Otvet:\boxed{(-4 \ ; \ -1)}$