SOLUTION: If r =2 and s = -7, what is the value of |r|-|s|? 5, or -5 , or 9 or -9 Is this 2-7 = -5 or 2- -7= 9? What does the bars mean i.e. are they like brackets? Most kids think

Algebra ->  Average -> SOLUTION: If r =2 and s = -7, what is the value of |r|-|s|? 5, or -5 , or 9 or -9 Is this 2-7 = -5 or 2- -7= 9? What does the bars mean i.e. are they like brackets? Most kids think       Log On


   

Question 157420: If r =2 and s = -7, what is the value of |r|-|s|? 5, or -5 , or 9 or -9
Is this 2-7 = -5 or 2- -7= 9? What does the bars mean i.e. are they like brackets? Most kids think the ans. is -5 but can't tll me why?
Answer by gonzo(654) About Me  (Show Source):
You can put this solution on YOUR website!

the bars mean absolute value of.
if you say |x| = 7, this is the same as saying the absolute value of x = 7.
if a number is positive then the absolute value of that number is positive.
if a number is negative then the absolute value of that number is the same number with a reversal of sign to make it positive.
|+7| = 7
|-7| = +7
in your example you ask for the value of |r| - |s|.
r = 2, so |r| = 2.
s = -7 so |s| = 7.
|r|-|s| means the absolute value of r minus the absolute value of s.
this means (+2) - (+7) which equals -5.