write an equation and solve for the variablewill send image

The equation can be written as,
[tex]\begin{gathered} 3+a+15=8+8+8 \\ a+18=24 \end{gathered}[/tex]The variable can be solved as,
[tex]\begin{gathered} a+18=24 \\ a=24-18 \\ a=6 \end{gathered}[/tex]Thus, the required value of varible is 6.