In AP n- th term:
an = a + ( n - 1 ) d
where
a = first term
d = common difference
In this case:
a = 3
a12 = a + 11 d = - 41
3 + 11 d = - 41
Subtract 3 to both sides.
11 d = - 44
d = - 44 / 11
d = - 4
a20 = a + 19 d = 3 + 19 • ( - 4 ) =
3 - 76 = - 73
The 12th term of an AP is -41 given that the first term is 3 find the 20th term
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