Din ecuatia 2 =>y=2/x inlocuiesti pe y in prima ecuatie
x²+(2/x)²=5 =>
x^4+4=5x²
x^4-5x²+4=0.
Faci substitutia x²=t t≥0
t²-5t+4=0 t1=1 t2=4
revii la substitutie
x²=1 =. x1=-1 , x2=1
x²4 =>x3=-2 , x4=2
Dar y=2/x => y1=2/-1=-2 y2=2/1 y2=2
y3=2/-2 y3=-1
y4=2/2=1
