Answer:
1.8
Step-by-step explanation:

 
        
             
        
        
        
A1. 12 i.e option D
A2. 3n-7 i.e option A
A3. -6n+20 i.e option D
A4. -70 i.e option C
Step-by-step explanation:
aₙ = a₁ + (n - 1) × d  
aₙ	=	the nᵗʰ term in the sequence
a₁	=	the first term in the sequence
d	=	the common difference between terms
Using the above formula to solve the first part, we have :
For the second part, we have :
For the third part, we have : 
For the fourth part, we have :
 
        
             
        
        
        
Answer:
 8) answer=5 9)answer=15
Step-by-step explanation:
all you have to do is replace in the following formula

Where
 X1: is the first number of the first point
 Y1: is the second number of the first point
X2:  is the first number of the second point
Y2: is the second number of the second point
you replace in the formula and solve
I attach solution
 
        
             
        
        
        
Answer:
A!
Step-by-step explanation:
open circle = the number it's on isn't an answer
the arrow is pointing left, the negative side so it's less than :)
 
        
             
        
        
        
This intersection means that u have to find the same number in both sets
the answer is 3 , 7 , 13
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