$8a+4-2=3$
Subtract the numbers$8a+2=3$
Move the constant to the right-hand side and change its sign$8a=3-2$
Subtract the numbers$8a=1$
Divide both sides of the equation by $8$$\begin{align*}&a=\frac{ 1 }{ 8 } \\&\begin{array} { l }a=0.125,& a={2}^{-3}\end{array}\end{align*}$