We just kind of went to the smallest possible function, and actually the smallest possible function would have been one of these terms, but we just found the derivative of this, which was 15 x squared minus 7, and then we just used the principle that the derivative of kind of a function is just the derivative of each of its parts-- well, actually, the derivative of-- we figured out the derivative of this inner piece, which was 15x squared minus 7, and then we multiplied it times the derivative of this slightly larger piece, which is 5 times this entire expression to the fourth, then we added it to the derivative of 3x to the minus 2.