Discussion
A bowl contains 500 marbles. There are x red marbles and y blue marbles in the bowl. Which one of the following expresses the number marbles in the bowl that are neither red nor blue?
| (A) | 500 + x − y |
| (B) | ... |
| (C) | ... |
| (D) | ... |
| (E) | ... |
| (F) | ... |
The solution is
Posted: 02/26/2012 15:46
How does 500-(x+y) = 500-x-y?
Posted: 02/27/2012 00:34
Hi Shaker, thanks for using the app and posting a question here. This is called the distributive property. It is best to think of the negative sign in front of an expression within parentheses as -1 times the terms within the parentheses. So, think of 500 - (x+y) as 500 -1*(x+y) = 500 -1*x -1*y = 500 -x-y