Answer :
[tex]\begin{gathered} 2(g-h)=b+4 \\ 2g-2h=b+4 \\ \text{add 2h to both sides} \\ 2g-2h+2h=b+4+2h \\ 2g=b+4+2h \\ \text{divide both sides by 2} \\ \frac{2g}{2}=\frac{b+4+2h}{2} \\ g=\frac{b+4+2h}{2} \\ g=\frac{b}{2}+2+h \end{gathered}[/tex]