X is given as the values between -5 and 5 with a spacing of 0.5
Y consists of the values 20.773, 15.04, 12.9, 9.5, 7.5, 4.3, 2.4, 1, 0.2, 0, 0, 0.6, 2.1, 3.9, 6, 8, 12, 14, 19, 23
Calculate the coefficients a, b, and c fo the polynomial of degree 2:
Define the polynomial function f as well and calculate the f(7)