The following points are given:

x 1 2.2 3.7 6.4 9 11.5 14.2 17.8 20.5 23.2
y 12 9 6.6 5.5 7.2 9.2 9.6 8.5 6.5 2.2

a. Fit the data with a first-order polynomial. Make a plot of the points.
b. Fit the data with a second-order polynomial. Make a plot of the points.
c. Fit the data with a third-order polynomial. Make a plot of the points.
d. Fit the data with an fifth-order polynomial. Make a plot of the points and the polynomial.