Explicație pas cu pas:
[tex] \bf x + y = 12 \: \: \: \: \: \bigg|^{2} [/tex]
[tex] \bf (x + y )^{2} = 12 ^{2} [/tex]
[tex] \bf x^{2} + 2 \cdot \green{\underline{x \cdot y }} + y^{2} = 144[/tex]
[tex] \bf x^{2} + 2 \cdot 23 + y^{2} = 144[/tex]
[tex] \bf x^{2} + 46 + y^{2} = 144[/tex]
[tex] \bf x^{2} + y^{2} = 144 - 46[/tex]
[tex] \red{ \boxed{ \: \bf x^{2} + y^{2} = 98 \: }}[/tex]
