Question

Решите систему
x^2+y^2=41
xy=20

Answer 1

(x+y)-2xy=41

(x+y)²-40=41
(x+y)²=81
x+y=9
xy=20

x=9-y

9y-y²=20
y²-9y+20=0
D=81-80=1
y1=9+1/2=10/2=5
y2=9-1/2=8/2=4
x1=9-5=4
x2=9-4=5