Answer:
[tex]D = \frac{2}{3} (F+ G) \\ F + G = D \div \frac{2}{3} \\ \\ F+ G = D \times \frac{3}{2} \\ \\ F +G = \frac{3D}{2} \\ \\ G = \frac{3D}{2} - F[/tex]
I hope I helped you^_^
