(4-3n-5n2)
+( -2+n-3n2)
____________________
    -2-2n-8n2
        
                    
             
        
        
        
Substitute answers in, a = 3 and b = 2.
(3^2 - 2^2)/(3+2)
= (9-4)/5
= 5/5
= 1
        
             
        
        
        
Answer:
241 tons 
Step-by-step explanation:
312-170=142
142÷2=71
170+71=241
241+71=312
train B weighs 241 tons
 
        
                    
             
        
        
        
<u>Answer:</u>
$14
<u>Step-by-step explanation:</u>
Assuming the cost of folder to be  , then the cost of notebook will be
, then the cost of notebook will be  and the cost of set of pencils will be
 and the cost of set of pencils will be  .
.
Cost of the folder = $2
Cost of notebook  = 4 × 2 = $8
Cost of pencil = 2 × 2 = $4
Total cost of 1 folder, 1 notebook and 1 set of pencils = $2 + $8 + $4 = $14