The answer is 20p. P represents the number of boxes she buys and 20 is how many pens are in each box.
        
             
        
        
        
6) x= 2, angle = 90 degrees obviously
7) Im not sure on this one
8) x = 5
9) x = 1
        
                    
             
        
        
        
Answer:
DB = CA (Proved)
Step-by-step explanation:
Statement 1.
∠D = ∠C, M is the midpoint of DC and ∠1 = ∠2
Reason 1.  
Given
Statement 2.
Between Δ DBM and Δ CAM,  
(i) DM = CM,
(ii) ∠D = ∠C  and  
(iii) ∠DMB = ∠CMA
Reason 2.
(i) given  
(ii) given and  
(iii) ∠ DMB = ∠1 + ∠AMB and  ∠CMA = ∠2 + ∠AMB
Since ∠1 = ∠2, so, ∠DMB = ∠CMA.
Statement 3.
Δ DBM ≅ Δ CAM
Reason 3.
By angle-side-angle rule.
Statement 4.
DB = CA
Reason 4.
Corresponding sides of two congruent triangles. (Answer)
 
        
             
        
        
        
If you would like to write a * b + c in simplest form, you can do this using the following steps:
a = x + 1
b = x^2 + 2x - 1
c = 2x
a * b + c = (x + 1) * (x^2 + 2x - 1) + 2x = x^3 + 2x^2 - x + x^2 + 2x - 1 + 2x = x^3 + 3x^2 + 3x - 1
The correct result would be x^3 + 3x^2 + 3x - 1. 
        
                    
             
        
        
        
Answer:
5
Step-by-step explanation:
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