Question 95683
explain why there is no value of x for which the expressions x + 3 and x + 4
are equal? 
My 7th grade son has this question on one of his worksheets and sadly I am
unable to help him. 
Thanks so much in advance for your help

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<pre><font size = 5 color = "indigo"><b>
If there were such a value for x, then you could 
subtract x from both sides like this:

                  x + 3 = x + 4
                 -x      -x
              -------------------
                  0 + 3 = 0 + 4
                      3 = 4

That is, if there were such a value for x then 
3 would have to equal to 4. But 3 does not equal
4, so therefore assuming there was such a value 
for x is wrong.  Therefore there can be no such 
value for x.

Edwin</pre>