For each of the following polynomials, apply either the Muller's method or the Bairstow's method to find all real or complex roots. Analyze and contrast performance between the two methods. Plot the functions to choose root guesses appropriately. You can apply any simplifications you deem appropriate prior to applying the numerical methods.

f(x) = -2 + 6.2x - 4x2 + 0.7x3