Given the following system of linear equations b – c + d + 2f = 0 2a + 5b – 2c – d + 3e + 6f = 6 a – b – 2d + 6e + 7f = 8 a + b + c – d – e – 6f = 3 3a – 9b + 4c – 5d – e + 2f = -1 -2a – 3b + 3c + 2d + e = 11 write the system in the form Ax = b. Then, write a MATLAB program that contains the following: a. a function that performs Gaussian elimination to find the upper triangular form of the matrix A and the corresponding vector b, and b. a function that performs back substitution to solve the system of equations. For this function, think about matrix indices and the pattern involved in back substitution.