the last term of an ap 2,5,8,11 is x.the sum of terms of ap is 155.find the value of x
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Sn= n÷2(2a+(n-1)d)
155=n÷2(2×2+(n-1)3)
155=n÷2(3n+1)
310=3n^2+n
3n^2+n-310
by solving we get
n=10
then last term =
a+ (n-1)d= 2+(10-1)3=
2+27=29
155=n÷2(2×2+(n-1)3)
155=n÷2(3n+1)
310=3n^2+n
3n^2+n-310
by solving we get
n=10
then last term =
a+ (n-1)d= 2+(10-1)3=
2+27=29
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