What is Gaussian Elimination with backward substitutions?

Explain your answer using your own example with MATLAB.  Create a 3×3 matrix by using the following command in MATLAB:

>>d = rand(3,3)

After explaining the Gaussian elimination, solve your matrix equation using section 6.3:

x = inv(A) * B  

or 

x = AB

Copy and paste in the edit window to SHOW ALL YOUR Work.