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. 
 
        
             
        
        
        
Step-by-step explanation:
let's simply do the multiplications and then compare with the original.
(x-m)² + n
right ?
or is it

let's go for the first. 
x² - 2mx + m² + n = x² - 3x
-2mx + m² + n = -3x
fun there we see two things :
-2m = -3
m = 3/2
and
m² + n = 0
(3/2)² = -n
9/4 = -n
n = -9/4
so our transformed expression looks like
(x - 3/2)² - 9/4
 
        
             
        
        
        
Answer:
Part A = the middle one 
Part B = 4 days 
Step-by-step explanation:
1,300 / 4 = 325
325 x 4 = 1,300