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Mathematics 8 Online
OpenStudy (anonymous):

math homework help? |y+4| < 1 a. -5 < y < -3 b. -3 < y < 5 c. -4 < y < 1 d. 1 < y < 4

OpenStudy (anonymous):

First you need to save the problem on the top. Do you know how to do that?

OpenStudy (anonymous):

Well you need to put it into absolute value right?

OpenStudy (anonymous):

It becomes two inequalities.

OpenStudy (anonymous):

It is in absolute value

OpenStudy (anonymous):

\[ y+4<1 \]and \[ -(y+4)<1 \]

OpenStudy (anonymous):

then you subtract 4?

OpenStudy (anonymous):

Yes, for the first formula.

OpenStudy (anonymous):

and the second one you distribute the negative?

OpenStudy (anonymous):

You can, or you can divide out \(-1\) on both sides.

OpenStudy (anonymous):

Generally you want to do the operation outside of the parenthesis first when isolating variables.

OpenStudy (anonymous):

so -y - 4 < 1

OpenStudy (anonymous):

yes

OpenStudy (anonymous):

and you add 4 to get y = -5 and in the first equation y = -3

OpenStudy (anonymous):

There is no equals sign.

OpenStudy (anonymous):

would that mean it's a?

OpenStudy (anonymous):

For the first inequality, we would get: \[ y<-3 \]

OpenStudy (anonymous):

For the second inequality we start at: \[ -(y+4)<1 \]Then we add \(y+4\) to both sides.\[ 0 < 1+y+4 \]

OpenStudy (anonymous):

Then we subtract the parts that aren't \(y\)\[ -5<y \]

OpenStudy (anonymous):

Does this make sense?

OpenStudy (anonymous):

i think so.. -5 < y < -3 right?

OpenStudy (anonymous):

Yes.

OpenStudy (anonymous):

okay thank you :)

OpenStudy (anonymous):

But could you do it on your own next time?

OpenStudy (anonymous):

yes

OpenStudy (anonymous):

!(-5) +4 ! < 1 !-1! < 1 !1! < 1 1 < 1 not true

OpenStudy (anonymous):

That is why it is \(-5<y\) and not \(-5\leq y\).

OpenStudy (anonymous):

!(-3)) + 4 ! < 1 !1 ! <1 not true

OpenStudy (anonymous):

i got 100% thank you so much!

OpenStudy (anonymous):

We did not say that \(y=-3\) or \(y=-5\). It must be between.

OpenStudy (anonymous):

! (-4) + 4! < 1 !0)! < 1 true

OpenStudy (anonymous):

!(1) + 4! < 1 !(5) < 1 not true so answer is c

OpenStudy (anonymous):

i got it right when i chose a

OpenStudy (anonymous):

If you chose a : -5 < y < -3 then !y + 4! < 1 is ! (-5) + 4! < 1 ! -1! < 1 !(-1)! is 1 so 1 < 1 which is not true. so you would have got the answer wrong

OpenStudy (anonymous):

well i got it right :) sorrry

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