d is easy, since A6-A4 = 2d, so
2d = -6
Now you can find a, since a+2d = -4
S12 = 12/2 (2a+11d)
The fourth and sixth term of an arithmetic progession are -4 and -10 respectively. Find
A.the common difference
B.the first term
C.sum of the first twelve terms
1 answer
1 answer