# Rearranging algebraic formula when subject is on both sides

I have run into some difficulty with a question on making a variable the subject of an equation where the variable is on both sides.

I am really struggling to find a method for making "a" the subject of an equation which looks like the below:

$$12d - \dfrac{3}{a} = 7 - \dfrac{6d}{a}$$

Please note this is not the exact question. I understand that the fractions need to be cleared by multiplying both sides. However, when starting this way the equation becomes very messy and I get stuck.

Thanks.

HINT: If $ax+ay=z\Rightarrow a(x+y)=z$.
The '$\Rightarrow$' means 'implies that'.