I can’t understand because I speak English
Answer:
10 i think
Step-by-step explanation:
Greetings :)
To find slope of two points we will need to use this equation: 
( 6 , -12 ) ( 15 , -3 )
Now let's replace the equation with the numbers. (it will be a fraction).
= 
The equation equals 9 over 9, which also equals 1.
The slope of the line is 1.
Answer:
arithmetic progression problem