If  ~$\frac{7x}{3}+a=8$~ and a > 8, then, in terms of a,  ~$\frac{3x}{7}=$~

~$\frac{1}{a}+\frac{1}{8}$~

~$\frac{1}{8}-\frac{1}{a}$~

~$\frac{1}{8-a}$~

~$\frac{3}{7}\left ( 8-a \right )$~

~$\frac{9}{49}\left ( 8-a \right )$~