Răspuns:
Explicație pas cu pas:
[tex]\bf Fie~ ~\overline {ab}~~numarul ~de ~doua~ cifre[/tex]
[tex]\bf a \cdot b = 6[/tex]
[tex]\bf \blue{\underline{~a = 1~}} \Rightarrow \green{\underline{~b = 6~}}\Rightarrow \red{\boxed{\bf~ \overline{ab}=16~}}[/tex]
[tex]\bf \blue{\underline{~a = 2~}} \Rightarrow \green{\underline{~b = 3~}}\Rightarrow \red{\boxed{\bf~ \overline{ab}=23~}}[/tex]
[tex]\bf \blue{\underline{~a = 3~}} \Rightarrow \green{\underline{~b = 2~}}\Rightarrow \red{\boxed{\bf~ \overline{ab}=32~}}[/tex]
[tex]\bf \blue{\underline{~a = 6~}} \Rightarrow \green{\underline{~b = 1~}}\Rightarrow \red{\boxed{\bf~ \overline{ab}=61~}}[/tex]
[tex]\bf \pink{\boxed{\bf~ \overline{ab}~\in~\big\{16,23,32,61\big\}~}}[/tex]
