writing a Matlab program solving linear equation system. Using the scaled partial pivoting method and keep the index vector in the Gauss elimination step. Also program the backward evaluation step. Write the program as a function, with the following variables (in the exact order) as input. 1) n, an integer for the size of the matrix A. 2) A, a n*n matrix, with single precision. 3) b, a n entry vector, with single precision. The output: return the following variable from your program, in the exact order. Notice, do not print your solution on the screen. Use the return command. 1) x, the n entry solution vector, with single precision. 2) l, the n entry vector, which is the final index vector. Use integer format.