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Unformatted text preview: tional expressions if we
need to, although they rarely are.
There is an unspoken rule when dealing with rational expressions that we now need to address.
When dealing with numbers we know that division by zero is not allowed. Well the same is true
for rational expressions. So, when dealing with rational expressions we will always assume that
whatever x is it won’t give division by zero. We rarely write these restrictions down, but we will
always need to keep them in mind.
For the first one listed we need to avoid x = 1 . The second rational expression is never zero in
the denominator and so we don’t need to worry about any restrictions. Note as well that the
numerator of the second rational expression will be zero. That is okay, we just need to avoid
division by zero. For the third rational expression we will need to avoid m = 3 and m = -2 .
The final rational expression listed above will never be zero in the denominator so again we don’t
need to have any restrictions.
The first topic that we need to discuss...
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- Spring '12