Question

how do you work this?
3|y-9|<27

Answer 1

To do this, first:
divide by 3, you're left with:
I y-9 I<9
Because it is an absolute value, you'll have two equations:
y-9<-9 y-9<9
y<0 y<18

Answer 2

Well if you we have |f|<a where a is positive, then we know that -a<f<a .
If we had |f|>a where a is positive, then we have f>a or f<-a.
We have the first case I mentioned.
One of the inequalities mentioned by @zeinas. is a little off.