The amount of fabric needed for Jimmy's costume is not stated, we can only determine the amount needed for Rob's costume, which makes it impossible to compare the amounts needed for both of their costumes. If this omission was an error, then you can find the difference between these amounts if the amount needed for Jimmy's costume is stated explicitly.
Step-by-step explanation:
The number of yards of fabric needed for Robs costume is (7/8+1/2+1 3/4)÷2
Assuming 1 3/4 is a mixed fraction.
= (7/8 + 1/2 + 7/4) ÷ 2
= (7 + 4 + 2) ÷ (8 × 2)
= 13/16 yards
Suppose 2 yards of fabric is needed for Jimmy's costume, then comparing with Rob's yards, we see that Jimmy's costume requires (2 - 13/16 = 19/16) more yards than Rob's costume.
As there are 81 tiles total, that makes your area 81. Being a square, that makes your area equation A=s^2. As you need a side, this makes your equation s=√A. Plugging in 81 as A, we get s=√81=9, so an edge has 9 tiles.
X is always dependant to Y. so that should answer the 1st one. the 2nd looks to be around 17-18. 17.5 maybe. and the 3rd is yes cause he does not go to the pool so it isnt any cost.
-3 x -26 = 78
meaning the answer is D.
The reason the answer is D, is because two negatives when multiplied or divided become positive. Only when multiplied or divided does this occur.
ANSWER

EXPLANATION
The given exponentiial expression is

We simplify using the rule:

We apply this property to get:

We simplify to get;

We rewrite as a positive index to get;
