Question

$\left \{ {{x+y=12} \atop {xy=35}} \right.$

Answer 1

x=12-y
(12-y)*y=35

x=12-y
12y-y²=35

x=12-y
y²-12y+35=0

D=144-140=4
y1= (12-2)/2= 5
y2= (12+2)/2= 7
x1= 7
x2= 5
Ответ: (7;5), (5;7)