If 3+5+7+9+....nth term=288, then n= ?
hafeezhtech:
is the value of n 144
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it is a a.p.
so here
a=3
d=5-3=2
n= no. of terms.
I am taking question's n= x
sum of n terms =n/2[2a+(n-1)d]
sum of n terms = n/2[2×3 +(n-1)2]
288=(n÷2)[(2)(3+n-1)
288=n(2+n)
n²+2n-288=0
n²+26n-24n-288=0
n(n+26)-24(n+26)=0
(n-24)(n+26)=0
n-24=0 n+26=0
n=24 n=-26 (no. of terms can't be negative)
so no. of terms are 24
so here
a=3
d=5-3=2
n= no. of terms.
I am taking question's n= x
sum of n terms =n/2[2a+(n-1)d]
sum of n terms = n/2[2×3 +(n-1)2]
288=(n÷2)[(2)(3+n-1)
288=n(2+n)
n²+2n-288=0
n²+26n-24n-288=0
n(n+26)-24(n+26)=0
(n-24)(n+26)=0
n-24=0 n+26=0
n=24 n=-26 (no. of terms can't be negative)
so no. of terms are 24
you made mistake while doing splitting the middle term
n2 +2n - 288 = 0
n2 18n - 16n - 288
n2+18n - 16n - 288*
so, the answer is 16 not 24
please change the answer
OK bro
there is no option for changing the answer I am sorry for my mistake
bro it would be near the 5 star rating just on the right side of it their is a option for edit
thanks comments and edit would be there
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