21 * (-1) = -21 
21 + (-1) = 20
        
                    
             
        
        
        
Answer:
Step-by-step explanation:
Let the number = x
8x - 13 = 4x + 3              Add 13
8x = 4x + 3 + 13             Combine
8x = 4x + 16                   Subtract 4x
8x - 4x = 16                    Combine
4x = 16                           Divide by 4
x = 16/4
x = 4
 
        
             
        
        
        
Answer:
since -3.73 is less than 1.645, we reject H₀.    
Therefore this indicate that the proposed warranty should be modified 
Step-by-step explanation:
Given that the data in the question;
p" = 13/20 = 0.65
Now  the test hypothesis;
H₀ : p = 0.9
Hₐ : p < 0.9
Now lets determine the test statistic;
Z = (p" - p ) / √[p×(1-p)/n]
= (0.65 - 0.9) /√[0.9 × (1 - 0.9) / 20]  
= -0.25 / √[0.9 × 0.1 / 20 ]
= -0.25 / √0.0045
= -0.25 / 0.067
= - 3.73
Now given that a = 0.05, 
the critical value is Z(0.05) = 1.645 (form standard normal table)
Now since -3.73 is less than 1.645, we reject H₀.    
Therefore this indicate that the proposed warranty should be modified 
 
        
             
        
        
        
Answer:
C. m∠4 = m∠8
D. m∠2 = m∠7
Step-by-step explanation:
Here, we use the principles of alternate angles, corresponding angles and vertically opposite angles to confirm which of the statements are true. Alternate angles are always equal, corresponding angles are equal, likewise vertically opposite angles.
From the given question, it was given that a is parallel to b. Thus, it can be observed and deduced that;
m∠4 = m∠8  (corresponding angles)
and
m∠2 = m∠3 (vertically opposite angles)
m∠3 = m∠7 (corresponding angles)
So that,
m∠2 = m∠7  
 Thus in the question, statements C and D are true.