2. Sum of the first 21 terms of an AP is 1071. Wh
is the first term if the common difference is 6?
Answers
Answered by
0
Answer:
s21=1071.
d=6.
a=?.
sn=n/2[2a+(n-1)d].
s21=21/2[2a+(21-1)(6)].
1071=21[a+(20)(6)].
1071=21[a+120].
1071/21=a+120.
51=a+120.
a=51-120.
a=-69. (Because +×-=- & largest number is important).
I think this is your answer.
Answered by
0
Answer:
Step-by-step explanation:
An= a+ (n-1)d
1071 = a + 20× 6
1071 = a+ 120
a= 1071 - 120
a = 951
Therefore, first term is 951
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