Matlab least square fit

Consider the data: a. Find and display the equation of the least squares "best fit" line for the data (x, y). b. Plot the original discrete data (x, y) using red 'o' symbols and the best-fit line in black on a single plot, using. c. Find and display the equation of the least squares "best fit" cubic equation for the data (x, z). d. Below the plot of part (b), plot the original discrete data (x, z) using green 'X' and the best-fit cubic function on a single plot, using values for x between 0 and 6, with increments of 0.1