Question

What is the nth ternm of this sequence -4,1,6,11,16,

a 5n-4
b -4n+5
c -9n
d 5n-9

Answer 1

d. (5n-9)

Explanation:

• First term = -4
• Common difference = 1-(-4)=1+4=5
• Formula used: L =a+(n-1)d

where, L is the last term;

a is the first term ;

n is the number of terms;

and d is the common difference.

• L = -4+(n-1)5= -4+5n-5 = 5n-9

Therefore, the last term is (5n-9).

Answer 2

• d. 5n-9

Explanation:

Given sequence:

• -4, 1, 6, 11, 16, ...

It is an AP with:

• The first term is a = -4
• Common difference is d = 5

Nth term of this sequence is:

• aₙ = a + (n - 1)d
• aₙ = - 4 + 5(n - 1) = -4 + 5n - 5 = 5n - 9

Correct option is d.