[tex] \huge \boxed{\mathfrak{Question} \downarrow}[/tex]
[tex] \large \boxed{\mathfrak{Answer \: with \: Explanation} \downarrow}[/tex]
[tex] \sf \: D = Ga+3 { h }^{ 3 } a[/tex]
Swap sides so that all variable terms are on the left-hand side.
[tex] \sf \: Ga+3h^{3}a=D [/tex]
Combine all terms containing a.
[tex] \sf\left(G+3h^{3}\right)a=D [/tex]
Divide both sides by [tex]\sf\:G+3h^{3}[/tex].
[tex] \sf\frac{\left(G+3h^{3}\right)a}{G+3h^{3}}=\frac{D}{G+3h^{3}} \\ [/tex]
Dividing by [tex]\sf\:G+3h^{3} [/tex] undoes the multiplication by [tex]\sf\:G+3h^{3}[/tex].
[tex] \boxed{ \boxed{ \bf \: a=\frac{D}{G+3h^{3}} }} \\ [/tex]
