Answer:
1.
C. 5y -7 is an algebraic expression difference with two terms.
Eileen is able to save 13% of her allowance each month.
How about this (see attached image):
Use the four cuts as shown in the image (red lines).
Then assemble 5 equal squares by the numbers: 1 center square and the rest are pieced together using two pieces as shown. All five together add up to the same area as original square because we use all pieces.
The way one gets a hint toward a solution is to see how an area of a square of length 1 can be split into 5 equal square areas:

which indicates we need to find a a triangle with sides 2 and 1 to get the hypotenuse of the right length. That gave rise to the cut pattern (if you look carefully, there are triangles with those side lengths).
The bench costs $450.
You first need to subtract the difference between the garden table and the bench from the total so they are equivalent, and then divide by two to find what the bench is on its own.
(The garden table costs $536, by the way. To find that, you just need to add its half of 900, 450, to the 86 you subtracted initially.)
Tell me if this doesn’t make sense, it’s sort of hard to explain!