Adding variables with negative exponents: r^-9 + r^-8

[jandmmartel]

This looks like a simple question, but I cannont find the answer!

r^-9 + r^-8= ??

I have not been able to find a similar problem to this anywhere any help would be appreciated.

Thanks! Julie

 

[Loren]

Re: Adding variables with negative exponents

Negative exponents follow the same rules as positive exponents.

If the problem stated --- x[sup:1xms7dhs]5[/sup:1xms7dhs] + x[sup:1xms7dhs]6[/sup:1xms7dhs] what would your answer be? Careful!

Examine something you can get your arms around, such as...

How much is 2[sup:1xms7dhs]3[/sup:1xms7dhs] + 2[sup:1xms7dhs]2[/sup:1xms7dhs]? Is that the same as 2[sup:1xms7dhs]3+2[/sup:1xms7dhs].

I think someone is trying to get you to come up with an invalid conclusion.