Am I second guessing myself?

[jazz]

Here is the problem and my work with a solution.

-6/7b^10*7/9b^8

First, I simplify

-6/7*7/9 =-1

then I had the exponent b^10 and b^8 which I add together and get b^18

my final answer is -1b^18

Is that correct?

 

[Deleted member 4993]

Here is the problem and my work with a solution.

-6/7b^10*7/9b^8

First, I simplify

-6/7*7/9 =-1

then I had the exponent b^10 and b^8 which I add together and get b^18

my final answer is -1b^18

Is that correct? - NO

6/7 * 7/9 = 6/9 = 2/3
.

 

[HallsofIvy]

Here is the problem and my work with a solution.

-6/7b^10*7/9b^8

This is extremely unclear. Is it (-6/7)(b^10)(7/9)(b^8)? If so then your answer is almost correct.

[quoteFirst, I simplify

-6/7*7/9 =-1[/quote]
This is just bad arithmetic! (-6/7)(7/9) You can cancel the "7"s to get -6/9. Now simplify that.

then I had the exponent b^10 and b^8 which I add together and get b^18

my final answer is -1b^18

Is that correct?

HOWEVER, if the problem is (-6/(7b^10))(7/(9b^8)) there is quite a different answer.