Answer:
x = 
Step-by-step explanation:
Given
=
( cross- multiply )
25 × 2x = 5 × 4
50x = 20 ( divide both sides by 50 )
x =
= 
Subtract any number from the next one.
-1 - (-6)
4 - (-1)
9 - 4
14 - 9
All of the above subtractions give the same answer.
That answer is the common difference.
No offense but the question dosen't make sense