Answer:
Standard form: 
Leading coefficient: 1
Step-by-step explanation:

The leading coefficient is 1 because the leading term is  .
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Answer:
5400 mm
Step-by-step explanation:
 
        
             
        
        
        
Let the width be w, then the length is 2w - 2.5.
Perimeter = 2(length + width)
40.6 = 2(2w - 2.5 + w) = 2(3w - 2.5)
3w - 2.5 = 40.6/2 = 20.3
3w = 20.3 + 2.5 = 22.8
w = 22.8/3 = 7.6
Therefore, width is 7.6 cm.
        
             
        
        
        
Expression without an equal sign with at least one variable
Hope this helps!