In an AP, the 7th term is 30 and the 10th term is 21. Find the first term, common difference and its n th term.
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3
we can write 7term as
a+6d=7term equation 1
and its 10 term =a+9d equation 2
from equation 1and 2we found that common difference =-3 and its first term will be 48 and its nth term will be 51-3n
Answered by
0
7=a+6d
10=a+9d
a+6d=30
a+9d=21
- - -
-3d=9
d=9/-3
d=3
a+6d=30
a+6*3=30
a+18=30
a=30-18
a=12
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