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<b>let </b><font color="Maroon" title="c1">p1</font>, <font color="Maroon" title="c2">p2</font> be   <a href="zf_lang.html#NM2" title="ZF_LANG:NM.2">ZF-formula</a>;<br/><b>let </b><font color="Maroon" title="c3">x1</font>, <font color="Maroon" title="c4">y1</font>, <font color="Maroon" title="c5">z1</font>, <font color="Maroon" title="c6">x2</font>, <font color="Maroon" title="c7">y2</font>, <font color="Maroon" title="c8">z2</font> be   <a href="zf_lang.html#NM1" title="ZF_LANG:NM.1">Variable</a>;<br/>















<b>assume </b><a NAME="E1:14"/><i><font color="Green" title="E10">A1</font></i>: 
 <a href="zf_lang.html#K17" title="ZF_LANG:func.17">Ex</a> <font color="Maroon" title="c3">x1</font>,<font color="Maroon" title="c4">y1</font>,<font color="Maroon" title="c5">z1</font>,<font color="Maroon" title="c1">p1</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="zf_lang.html#K17" title="ZF_LANG:func.17">Ex</a> <font color="Maroon" title="c6">x2</font>,<font color="Maroon" title="c7">y2</font>,<font color="Maroon" title="c8">z2</font>,<font color="Maroon" title="c2">p2</font>
 ;<br/>

<a NAME="E2:14"/>
( <font color="Maroon" title="c3">x1</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c6">x2</font> &amp;  <a href="zf_lang.html#K15" title="ZF_LANG:func.15">Ex</a> <font color="Maroon" title="c4">y1</font>,<font color="Maroon" title="c5">z1</font>,<font color="Maroon" title="c1">p1</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a>  <a href="zf_lang.html#K15" title="ZF_LANG:func.15">Ex</a> <font color="Maroon" title="c7">y2</font>,<font color="Maroon" title="c8">z2</font>,<font color="Maroon" title="c2">p2</font> )
 
<b>by </b><i><a class="txt" href="zf_lang1.html#E1:14"><i><font color="Green" title="E10">A1</font></i></a>, <a class="ref" href="zf_lang.html#T51" title="ZF_LANG:th.51">ZF_LANG:51</a></i>;<br/>
<b>hence </b><a NAME="E3:14"/>
( <font color="Maroon" title="c3">x1</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c6">x2</font> &amp; <font color="Maroon" title="c4">y1</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c7">y2</font> &amp; <font color="Maroon" title="c5">z1</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c8">z2</font> &amp; <font color="Maroon" title="c1">p1</font> <a href="hidden.html#R1" title="HIDDEN:pred.1">=</a> <font color="Maroon" title="c2">p2</font> )
 <b>by </b><i><a class="ref" href="zf_lang1.html#T20" target="_self" title="ZF_LANG1:th.20">Th20</a></i>;<br/>


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