1. (Problem 5.7): For the function f(x) = -12 21x + 18x2 2.75x3 (a) Plot the function, f (x)versus x (with appropriate labels). (b) Write an m-file script using bisection method to find a root of f(x), with initial guesses (-1 and 0 ) and a stopping criterion of 0.1%, showing how many iteration needed to get such accuracy