the 14th term of an A.P is twice its 8th term . if its 6th term is -8 , then find the sum of its first 20 terms
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6
t14th =2T8
2a+13d=2(2a+7d)
2a+13d=4a+14d
a=-d/2
equation 1 is
2a+d=0
and eqn second is 2a+5d=-8
on subtracting both 4d=-8
d=-2
and by putting d we get a=1
hence when you got both
u can easily solve the sum of A.P
2a+13d=2(2a+7d)
2a+13d=4a+14d
a=-d/2
equation 1 is
2a+d=0
and eqn second is 2a+5d=-8
on subtracting both 4d=-8
d=-2
and by putting d we get a=1
hence when you got both
u can easily solve the sum of A.P
BEJOICE:
Dear 14th term is twice 8th term
nth term of AP is a+(n-1)d, not 2a+(n-1)d
now let me know who's answer is right
Don't get confused. My answer is 100% correct
okkk
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21
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