This is a little bit weird, but it's not hard if you just
do it one step at a time.
Here's the important part that you need to know
in order to solve this problem:
All four sides of a square are equal.
Got that ? Good.
Here we go.
-- First, take the left and right sides.
They must be equal, so
2y - 5 = y - 1
Add 5 to each side: 2y = y + 4
Subtract 'y' from each side: y = 4 .
The left side is y-1 = 3
The right side is 2y-5 = 2(4) - 5
= 8 - 5
= 3 .
Good ! We have the left and right sides equal.
Do we really need to do the other two sides ?
They told us it's a square, so can't we just say
the top and bottom are also 3 ?
Well, maybe. But maybe they're trying to trick us,
and the top and bottom aren't really 3 . I think
we ought to check it out. It's more good math practice.
-- Take the bottom side ... it's 3y-9 .
But you know what 'y' is !
We just calculated that y=4,
so
3y - 9 = 3(4) - 9 = 12 - 9 = 3 .
Great ! The bottom side is 3 .