Question

решить систему 
х-у=5
ху=14

Answer 1

$left { {{x-y=5,} atop {xy=14;}} right. \ x=5+y; \ y(5+y)=14; \ y^2+5y=14; \ y^2+5y-14=0; \ D=25-4*(-14)=25+56=81; \ y_1= frac{-5+9}{2} =2; \ y_2= frac{-5-9}{2} =-7.$
$x_1=2+5=7; \ x_2=-7+5=-2:$