Answer:
12.21
Step-by-step explanation:
8x-9y=11
First you move the 8x because you have to leave the 9y alone
8x-9y=11
-8x -8x
-9y=11-8x
Now you have to move the -9, so the inverse of multiplying is dividing so you divide -9.
-9y/-9= 11/-9 -8x/-9
since you can't have negative as a denominator it would be:
y= -11/9+8x/9
<span>You have to change the signs</span>
Answer:
Step-by-step explanation:
Pamela has 15 different books. In how many ways can she place her books on two selves so that there is at least one book on each shelf? (Consider the books in each arrangement to be stacked one next to the other, with the first book on each shelf at the left of the shelf.)
Initially, I thought that this would be fairly straight forward. There are two cases where either shelf could be empty and so we would subtract 2 from the total number of permutations which is obviously 15!. It is obvious now that both of these statements are false.
My previous thoughts didn't take into account the fact that there are two shelves and that the books could be stacked in such a way that 5 are on the top shelf and 10 are on the bottom, or 8 on top with 7 on bottom, or any number of other ways. I believe there are 214 ways the books can be distributed amongst the two shelves (keep in mind that each shelf has to have at least one book, 15−1=14) if the ordering of the books didn't matter, but it does. Is this correct?
