Question

The sum of n terms of an A.P. is 3n2+ 5. Which term of the A.P. equals 159?​

Answer 1

Answer:

152 term

Step-by-step explanation:

Sn=3n²+5

S1= 3(1)²+5

S1= 8

S1=a1= 8

S2= 3(2)²+5

S2= 17

a2=S2-S1

a2= 17-8

a2=9

a2-a1=d

9-8=d

1=d

a+(n-1)d=159

8+(n-1)1=159

n+7=159

n=159-7

n=152

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