x
step-by-step explanation:
( - 4 , -7 )
all the lines must parallel
coordinates of c = ( - 1 , 2 )
3 units left = ( -4 , 2 )
9 units down = ( - 4 , 11 )
10 - 8 = -2
8 - 6 = -2
etc, so -2 is the common difference