Answer:
The general rule is 
Step-by-step explanation:
Arithmetic sequence:
In an arithmetic sequence, the difference between consecutive terms is always the same, and this difference is called common difference.
The general rule of an arithmetic sequence is given by:

In which  is the first term and d is the common difference.
 is the first term and d is the common difference.
We can also find the nth term as a function of a term m, using:

a3 = -12 and a8 = -37
First we find the common difference. So






So

Finding the first term:

Since 



So the general rule is:


 
        
             
        
        
        
Answer:
C. -7
Step-by-step explanation:
See the picture for steps :)
 
        
             
        
        
        
Answer:
Statements:                                                 Reasons:
1) ∠2 and ∠4 are vertical angles               given
2) limes <em>m </em>and <em>n </em>intersect at <em>P                    </em>definition of vertical angles
3) ∠3 and ∠4 are linear pair                       definition of linear pair 
4) ∠2 and ∠3 are linear pair                       definition of linear pair
5) m∠3 + m∠4 =180                                     angle addition postulate
6) m∠2 + m∠3 =180                                     angle addition postulate
7) m∠2 + m∠3 = m∠3 + m∠4                   substitution property
8) m∠2 = m∠4                                             subtraction property
9) ∠2 ≅ ∠4                                                 definition of congruent(≅) angles
 
        
             
        
        
        
I’m not sure abt 21 but 22 is the second one and the 4th one. So 2,4.
        
             
        
        
        
Answer:
85 feet
Step-by-step explanation:
P=2L+2W where L is the length and W is the width. If the length is 50 feet longer than the width, we can write the expression L=50+W. Substituting into P=2L+2W we get P=2(50+W)+2W=100+2W+2W=100+4W. Since P=300, we can say 300=100+4W. Subtracting 100 from each side we get 200=4W. Dividing each side by 4 gives 50=W. Substituting this into L=50+W gives L=50+35=85. The length is 85 feet.