
| Surviving College Algebra |
| "When all you want is the grade" |

| Negative Exponents |
There
is another property that deals with exponents, it is
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Notice
that the negative sign in front of the exponent has absolutely nothing to do
with the result being negative or positive.
Example
Simplify
Applying
the property.
Example
Simplify
Applying the properties of exponents.
Answer!
Using
the property of negative exponents, another rule is
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This
entire idea of negative exponents is best understood thinking about it like
this, “ If you move a number or variable from one side
of a division property to another (side refers to top or bottom), it changes
the sign of its exponent.” This is very
important because there cannot be an answer with a negative exponent.
The
first step in solving any kind of problem with negative exponents is to first
make all the exponents positive. Remember to make a negative exponent positive
move it “across the line” or from the numerator (top) to the denominator
(bottom) or vice versa.
Example
Simplify
The
first thing is to move the
to the top and make it positive.
Now
apply the properties of exponents 3+5 = 8.
Answer!
Example
Simplify
The
first thing is to make all negative exponents positive. Move the
to the bottom
and the
to the top.
Combine
like bases (the x’s on top and the z’s on bottom).
Get
all the y’s on either the
top or bottom.
Note- To get the y’s all together, ask this question, “
Which side has the most y’s (top or
bottom)?” Look at their exponents and
realize there are 2 y’s on the top and 5 y’s on the bottom. Since there are more on bottom, the final
answer will have the y’s on
bottom. To find out how many, just
subtract the exponents. 5-2 = 3.
This
is almost the final answer. The last thing to do is to see if the numbers will
simplify, they will since 3 goes into both of them,
=
.
Answer!
Example
Simplify
Get
rid of the parentheses and raise everything in the parentheses to the 4th
power. Use the properties of exponents.
Notice
the * sign between the 2 and 5. This is
done so not to confuse oneself by thinking it is 25 instead of 2*54.
Make all the exponents positive by moving them to the other side.
Simplify
the a’s. Since there are more on top, leave them on
top and 8 –3 = 5. Also simplify the
5’s. Treat them just as if they were
letters. There are more 5’s on top and
4-2=2.
52=
25. And 2 * 25 = 50.
Answer!