[tex]xy=143=\ \textgreater \ x=143/y\\
(143/y)^2+y^2=290\\
20449/y^2+y^2=290\\
20449+y^4=290y^2\\
Notam\ y^2=t=\ \textgreater \ t^2-290t+20449=0=\ \textgreater \ t=121\ si t=169\\
y^2=121=\ \textgreater \ y=+/-11\\
y^2=159=\ \textgreater \ y=+/-13[/tex]
Avem cazurile:
a)y=11=>x=13
b)y=-11=>x=-13
c)y=13=>x=11
d)y=-13=>x=-11
