Ok, we have :
Let , so we have :
What is the common denominator ?
In one side, we have 3k and in the other side, 3.
So the common denominator is
To make such a thing, we will have to multiply the fraction on the right side by so that we will have 3k at the bottom.
But what is ?
A rule of exponents tells us :
Is it clear enough ? :x