Take a look at this equation
x
=
x
This equation is of course true in every aspect. This is the easiest example I could think of.
Even
though this is the case you can get the point. The equations that have this property happen to be
called identities. Here are a few examples of identities below
4
x
=
x
+
x
2 = 2
(
x
– 5)(
x
+ 5) =
x
2
– 10
All of these equations above are quite true for the value of
x
. The second example that is
provided is pretty interesting because it does not even have an x(2=2).
This obviously
means one can not depend on the value of x for the truthfulness. To make things more
simple, if you are trying to solve an equation such as this in an algebraically way then
you will know that the original equation has got to be an identity as well. This of course
has an infinite number of solutions.
Okay now take a look at this equation
x
+ 5 =
x
+ 4
There is no value for
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 Spring '10
 Sutherland
 Elementary algebra, Inflection

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