Question

3. The last term of a sequence given by Tn= n2 - 14n is 51.
The no. of terms in the sequence are
A) 15
B) 16
C17
D) 18
E) None of these

Answer 1

Answer:

C) 17

Step-by-step explanation:

Tn=n2-14 is 51.

Tn=51.

51=n2-14n

n2-14n-51=0

n2-17n+3n-51=0

n(n-17)+3(n-17)=0

(n-17)(n+3)=0

{n tern can never be negative(-)}

So,

n=17 Answer.