Question 705235
<pre>
There is no solution.

 p - 4 = -9 + p

We add -p to both sides

 p - 4 = -9 + p
-p           -p
---------------
    -4 = -9

When all variables are eliminated from an equation, and what is left
is a false statemenr, then that means there is no solution.  Such an
equation is called "a contradiction".

When all variables are eliminated from an equation, and what is left
is a true statement, that that means there are infinitely many solutions.

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Suppose we had had   x + 3 = 3 + x

  x + 3 = 3 + x
 -x          -x
---------------
      3 = 3

That is true so there are infinitely many solutions.  That is called "an
identity".

Edwin</pre>