Posted by tara on .
if you have a problem where you are multiplying numbers with exponents (both positive and negative) and your answer ends up with a negative exponent what is the reason you make a fraction out of it and put it on the bottom as a positive?
why cant you have a negative exponent in an answer?

college algebra 
drwls,
You are right. You can write the answer either way.
For example, if a and b are both positive,
x^a*x^b = x^(ab) or 1/x^(ba) 
college algebra 
tara,
but why cant there be a neg. on top? why do u move it to the bottom and make it positive?(note:neg6,5,2 and 4 are exponents)
(4a6b5)(7a2b4)= 28a5b9
the final answer will be 28b9
over
a5
my question was why do you move the "a" negative 5 to the bottom and make it a postive "a" 5
I hope i'm wording this right. 
college algebra 
drwls,
You can. Just move the exponent up or down between numerator and denominator and change the sign. It's the same number either way.