The sum of the first nine terms of an ap is 72 and the sum of the next four terms is 71.find the ap
2 answers
Please help me solve this problem
S9 = 72
S13-S9 = 71
9/2 (2a+8d) = 72
13/2 (2a+12d) - 72 = 71
Now solve for a and d as usual.
S13-S9 = 71
9/2 (2a+8d) = 72
13/2 (2a+12d) - 72 = 71
Now solve for a and d as usual.