Решите систему x+y=3 x^2+xy=5

Question

Решите систему
x+y=3
x^2+xy=5

Answer 1

X=3-y
(3-y)^2+(3-y)*y=5
9-6y+y^2+3y-y^2=5
-3y+9=5
-3y=-4
y=4/3
x=3-4/3=5/3
(5/3;4/3)

Answer 2

x+y=3
x^2+xy=5⇒x(x+y)=5⇒3x=5⇒x=5/3
5/3+y=3
y=3-5/3
y=4/3
(5/3;4/3)