determinati numarul x pt xare x^2+3^4=15^2

Răspuns :

[tex] x^{2} +3^{4}=15^{2}\\\\x^{2}=15^{2}-3^{4}\\ \\x^{2}=225-81\\\\x^{2}=144\\\\x=\sqrt{144} \\\\x=12[/tex]