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<b>let </b><font color="Maroon">a</font> be    <a href="hidden.html#M1">set</a> , <font color="Maroon">b</font> be    <a href="hidden.html#M1">set</a> , <font color="Maroon">x</font> be    <a href="hidden.html#M1">set</a> , <font color="Maroon">y</font> be    <a href="hidden.html#M1">set</a> , <font color="Maroon">x'</font> be    <a href="hidden.html#M1">set</a> , <font color="Maroon">y'</font> be    <a href="hidden.html#M1">set</a> ;<br/>

<b>assume </b><b>that </b><br/><a NAME="E1:75"/><i><font color="Green">E34</font></i>: 
<font color="Maroon">a</font> <a href="hidden.html#NR2" target="_self">&lt;&gt;</a> <font color="Maroon">b</font>
 <b>and </b><br/><a NAME="E2:75"/><i><font color="Green">E36</font></i>: 
<font color="Maroon">a</font>,<font color="Maroon">b</font> <a href="funct_4.html#K4" target="_self">--&gt;</a> <font color="Maroon">x</font>,<font color="Maroon">y</font> <a href="hidden.html#R1">=</a> <font color="Maroon">a</font>,<font color="Maroon">b</font> <a href="funct_4.html#K4" target="_self">--&gt;</a> <font color="Maroon">x'</font>,<font color="Maroon">y'</font>
 ;<br/>

<b>thus </b><font color="Maroon">x</font> = 
<span class="p1">(<span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font> <a href="funct_4.html#K4" target="_self">--&gt;</a> <font color="Maroon">x</font>,<font color="Maroon">y</font></span>)</span> <a href="funct_1.html#K1">.</a> <font color="Maroon">a</font>
<b>by </b><i>, </i>
<br/>.= 
<font color="Maroon">x'</font>
<b>by </b><i>, <a class="ref" href="funct_4.html#T6" target="_self">Th6</a>, </i>
;<br/>

<b>thus </b><font color="Maroon">y</font> = 
<span class="p1">(<span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font> <a href="funct_4.html#K4" target="_self">--&gt;</a> <font color="Maroon">x</font>,<font color="Maroon">y</font></span>)</span> <a href="funct_1.html#K1">.</a> <font color="Maroon">b</font>
<b>by </b><i>, </i>
<br/>.= 
<font color="Maroon">y'</font>
<b>by </b><i>, <a class="ref" href="funct_4.html#T6" target="_self">Th6</a>, </i>
;<br/>


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