Discussion:  All Topics 
Topic:  Expressions vs Equations 
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Subject:  RE: Expressions vs Equations 
Author:  The Math Guy 
Date:  Jan 26 2011 
were evaluating (replacing x, y, & z with numbers) the expression, you don't
have an equation. If you looked at 3x+5 = 7...that is an equation. But for
3x+5, if x = 2, then your are evaluating the expression 3x+5 when x = 2 and your
evaluation might go something like this:
3x + 5:
3(2) + 5 =
6 + 5 =
11
The "=" sign is used to separate the different forms of the expression...
But the = sign is not what is making this evaluation process into an
equation.
On the other hand,if you did write
3(2) + 5 = 11, then that equation is an Identity...true for all times just
as
cos^2 X + sin^2 X = 1 for all values of X...an identity.
Art M.
 
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