We have the following equation
[tex]\frac{a}{3}-1.2=0.4[/tex]If we move -1.2 to the right hand side as +1.2, we get
[tex]\begin{gathered} \frac{a}{3}=0.4+1.2 \\ \frac{a}{3}=1.6 \end{gathered}[/tex]Now, we must move 3 to the right hand side as
[tex]a=3(1.6)[/tex]and finally, the answer is
[tex]a=4.8[/tex]