Answer: There are infinitely many solutions of this equation.
Step-by-step explanation:
The given equation : 
First we try to solve the above equation by combining the like terms (by reordering them), we get

Subtracting 3a from both sides (by using subtracting property of equality), we get
, which is absolutely a correct fact.
That means, the equation has infinitely many solutions as a can take any real value .
Thus , there are infinitely many solutions of this equation.