the 9th term of an ap is -32 the sum of its 11th and 13th terms is - 94 find the common difference
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Answer:
-5
Step-by-step explanation:
9th term = a+(9-1)d = a+8d = -32--(2)
11th term = a+(11-1)d = a+10d
13th term = a+(13-1)d = a+12d
a+10d+a+12d=-94
2a+22d=-94
a+11d=-47---(1)
(2)-(1):
-3d=15
d=-5
the common difference is equal to -5
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