Posted by brooke on Thursday, September 24, 2009 at 8:35pm.
Assistance needed.
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The | | signs mean "absolute value". When you take the absolute value of a number, you always take the numbers positive value. So |-5| = 5, |-21| = 21, |24| = 24, |5| = 5, and so on.
So, for the first expression, if we replace the x with 5, we get that:
|2*x-15| = |(2*5)-15| = |10-15| = |-5| = 5
There seems to be an error in your second expression, because there can't be any equals signs inside the || signs.
For the third expression we get that:
|w-x|-|10y-w| =
|-3-5| - |(10*3.5)-(-3)| =
|-8| - | 35 + 3| =
8 - 38 = -30