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<b>let </b><font color="Maroon">x</font> be   <a href="supinf_1.html#NM3">R_eal</a>;<br/><b>let </b><font color="Maroon">y</font> be   <a href="supinf_1.html#NM3">R_eal</a>;<br/>



 <a href="supinf_2.html#K3">-</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><a href="supinf_2.html#K3">-</a> <font color="Maroon">x</font></span>)</span> <a href="supinf_2.html#K2">+</a> <font color="Maroon">y</font></span>)</span> = 
<span class="p1">(<span class="default"><a href="supinf_2.html#K3">-</a> <span class="p2">(<span class="default"><a href="supinf_2.html#K3">-</a> <font color="Maroon">x</font></span>)</span></span>)</span> <a href="supinf_2.html#K4">-</a> <font color="Maroon">y</font>
<b>by </b><i/>
<br/>.= 
<font color="Maroon">x</font> <a href="supinf_2.html#K4">-</a> <font color="Maroon">y</font>

;<br/>
<b>hence </b><a NAME="E2:15"/>
(  <a href="supinf_2.html#K3">-</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><a href="supinf_2.html#K3">-</a> <font color="Maroon">x</font></span>)</span> <a href="supinf_2.html#K2">+</a> <font color="Maroon">y</font></span>)</span> <a href="hidden.html#R1">=</a> <font color="Maroon">x</font> <a href="supinf_2.html#K4">-</a> <font color="Maroon">y</font> &amp;  <a href="supinf_2.html#K3">-</a> <span class="p1">(<span class="default"><span class="p2">(<span class="default"><a href="supinf_2.html#K3">-</a> <font color="Maroon">x</font></span>)</span> <a href="supinf_2.html#K2">+</a> <font color="Maroon">y</font></span>)</span> <a href="hidden.html#R1">=</a> <font color="Maroon">x</font> <a href="supinf_2.html#K2">+</a> <span class="p1">(<span class="default"><a href="supinf_2.html#K3">-</a> <font color="Maroon">y</font></span>)</span> )
 ;<br/>


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