We are looking for dy/dx, and in this question, the key rule to remember is the chain rule.
Therefore the first thing to do is the easy step, take the 3 down and minus 1 from it, this will give 3(6x-13)2. But this is not the final answer as we have not also differentiated what is inside the bracket, hence we need to differentiate (6x-13), which is just 6, so we multiply this by the whole equation.
Therefore our answer will become 6*3(6x-13)2 = 18(6x-13)2