{x-y=2
{x+yx=20
розвяжите сис-му равнение!

$left { {{x-y=2} atop {x+yx=20}} right.$
$left { {{x=2+y} atop {x+yx=20}} right. [/tex [tex]2+y+y(2+y) = 20$
$2+3y+ y^{2} = 20$
$D = b^{2} - 4*a*c = 9 - 4*1*2 = 1$
$y1 = frac{-3-1}{2} = frac{-4}{2} = -2$
$y2 = frac{-3+1}{2} = frac{-2}{2} = -1$
$x1 = 2-2=0$
$x2 = 2-1 = 1$
ОТВЕТ: x1 = 0, y1 = -2 : x2 = 1, y2 = -1