If the length is four units greater than w, then it is equal to w+4.
        
             
        
        
        
P = L + L + w + w
72 = 2(L) + 2(L-4)
Distribute
72 = 2(L) + 2(L) - 8
Add like terms
72 = 4(L) - 8
Subtract 8 from both sides
64 = 4(L)
Divide both sides by 4
16 = L
The length is 16. Now substitute that in the equation for finding w.
w = L - 4
w = 
 
        
             
        
        
        
Answer:
6 weeks
Step-by-step explanation:
6*5=30
100+30=130
20*6=120
120+10=130
130=130
 
        
             
        
        
        
We can cosider this to be  a difference of 2 squares  so 
4x^4 - 9x^2 = (2x^2 - 3x)(2x^2 + 3x)   so D is one answer
also we could take x^2  out and get 
x^2(4x^2 - 9)  = C
        
             
        
        
        
$10.13
4 1/2=4.5
4.5x2.25=10.125
10.125 rounds to 10.13