that INV go past your eyes; to solve that system, FACTORIZE!"</p>
         <h2>How to use BACKSLASH solve A*x=b<a name="3"></a></h2>
         <p>First, let's create a square matrix A and a right-hand-side b for a linear system A*x=b.  There are many ways to solve this
            system.  The best way is to use x=A\b.  The residual r is a vector of what's left over in each equation, and its norm tells
            you how accurately the system was solved.
         </p><pre class="codeinput">format <span clas