Derivative : solution of exercise 4.9 - Basic math level

f(x) = 7 ^{x2 - 5x + 4}, find the derivative f'. We have here a real number (a constant) raised to the power of a quadratic function of x, g(x). You can differentiate such a function taking successively the natural logarithm and the derivative of both the left and right sides. You can use as well the derivative rules.