span></span></span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 1*x1 - 1*x2  =  2 </span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 2*x1 + 2*x2  =  1 </span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 3*x1 + 1*x2  =  6 </span>
<span class="r-in"><span><span class="fu">plotEqn</span><span class="op">(</span><span class="va">A</span>,<span class="va">b</span><span class="op">)</span></span></span>
<span class="r-out co"><span class="r-pr">#&gt;</span>   x[1] - 1*x[2]  =  2 