don't make it so hard on yourself ... on every iteration of a derivative, the derivative of (5x-1) becomes an additional factor
you don't need the product rule ...
So to find the 1st derivative I use the Chain Rule:
2nd:
Multiplication rule [f'(x)*g(x) + f(x)*g'(x)] and Chain Rule:
3rd:
Multiplication rule [f'(x)*g(x) + f(x)*g'(x)] and Chain Rule:
I think I got this one wrong but this is how I worked it out...have I done any step incorrectly here?