o valor de X será 4 pois 4 + 6 é igual a 10

[tex]\Large\displaystyle\text{$\begin{gathered} \sf{ x+6=10} \end{gathered}$}[/tex]

[tex]\Large\displaystyle\text{$\begin{gathered} \sf{ x=10-6} \end{gathered}$}[/tex]

[tex]\Large\displaystyle\text{$\begin{gathered} \boxed{\boxed{\sf{x=4}} } \end{gathered}$}[/tex]