Respuesta :
Answer:
-7
Step-by-step explanation:
a=9 a2=2 a3=-5 a4=-12
d = a4-a3 ,a3-a2, a2-a.
so:
d = -12-(-5) =-12+5 =-7
also;
d = -5-2 = -7
and
d= 2-9 =-7
so the common difference is -7
Answer:
-7
Step-by-step explanation:
We know that
Common difference = a2 - a1
=> 9 - 2
=> -7
