If -1 < 2y < 0, what are the possible values of |y| - y ?

(|y| is the absolute value of y)

I know the interval is 0 < y < 1 but I don't how to show it algebraically..

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- Jun 2nd 2012, 05:32 AMdonnagirlInequality problem
If -1 < 2y < 0, what are the possible values of |y| - y ?

(|y| is the absolute value of y)

I know the interval is 0 < y < 1 but I don't how to show it algebraically.. - Jun 2nd 2012, 05:46 AMPlatoRe: Inequality problem
- Jun 2nd 2012, 05:51 AMHallsofIvyRe: Inequality problem
- Jun 2nd 2012, 02:04 PMdonnagirlRe: Inequality problem
I thought the same too, but the solution of 0 < x < 1 came from collegeboard (it's a sample sat problem) How could they mislead us with the answer provided?

- Jun 2nd 2012, 02:21 PMPlatoRe: Inequality problem
- Jun 2nd 2012, 02:26 PMdonnagirlRe: Inequality problem
How did you get those two intervals plato? Where did the -y come from as well? and why is the 0.5 on the right hand side? I get it to look like -0.5 < y < 0 when I worked out the algebra

- Jun 2nd 2012, 02:41 PMPlatoRe: Inequality problem
**You are given**$\displaystyle -1<2y<0$.

Divide by two: $\displaystyle -0.5<y<0$. Multiply by $\displaystyle -1:~~0<-y<0.5$.

If you know that $\displaystyle -3<a<-1$ then $\displaystyle 1<|a|<3$. So from the given $\displaystyle 0<|y|<0.5$.

Add those two together: $\displaystyle 0<|y|-y<1~.$ - Jun 2nd 2012, 02:52 PMdonnagirlRe: Inequality problem
thank you plato, I got it now!