If The 12th term of an A.P is −28 and 18th term is −46. Find the 1st term and comon difference
Answers
Answered by
1
a+11d=-28
a+17d=-46
-5d=18
d=-18/5
Put the value of d in eq 1
Answered by
1
Answer:
First term=21
Common difference=-3
Step-by-step solution
Given-
a12=-28 and a18=-46
now,
a+11d=-28 eq.1
a+17d=-46 eq.2
on subtracting eq.1 from eq.2 , we get
6d=-18
d=-3
now,
putting the value of d in eq.1
a+11*(-3)=-12
a-33=-12
a=-12+33
a=21
Therefore, first term(a) is 21 and the common difference(d) is -3
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