How do you differentiate?

Say you have the term y=3X² . You start by bringing the power down and placing it in front of the 3 so they multiply like so y=2x3X² then next you take one away from the power like so y=2x3X¹ . This can then be simplified by solving 2x3 and realising that X¹ is the same as just X. This means it can be written as y=6X.