Question

The sum of n terms of an AP is 3° +5n, which terms of AP is 164
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Answer 1

Step-by-step explanation:

Sn=3n2+5n

S1=a1=3(1)2+5(1)=8

S2=3(2)2+5(2)=22

S2=22=a1+a2

a2=22-8=14

d=a2-a1=14-8=6

nth term value is 164,then what is n?

nth term=a+(n-1)d

164=8+(n-1)6

164-8 / 6=n-1

156/6=n-1

26+1=n

n=27

So 27thterm is 164.

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Answer 2

Step-by-step explanation:

sum of n terns = 3n²+5n

so a1= 3(1)²+5(1)

a1= 8

and s(a2) = 3(2)²+5(2)

s(a2)= 22

a2=s(a2)-a1

a2=22-8

a2=14

d=a2-a1

d=14-8

d=6

an=a1+(n-1)d

164=8+(n-1)6

164-8=(n-1)6

156/6=(n-1)

26=n-1

26+1=n

27=n

so 164 is 27 term of ap