Question

What are the first four terms of the sequence represented by the expression `n(n-1)-5`?

Answer 1

`-5, -3, 1, 7`

Explanation:

In sequences, n gives the position of the term.
For the first term, n = 1, for the second term, n=2 and so on.

If `n =1, "substituting gives:" 1(1-1) -5 = 0-5 = -5`
`n = 2 rArr 2(2-1)- 5= 2-5 = -3`
`n = 3 rArr 3(3-1) -5 = 6-5 = 1`
`n = 4 rArr 4(4-1) -5 = 12-5 = 7`

Answer 2

-5, -5, -3, 1

Explanation:

Put gradually natural numbers in n so,
if you put n=0 then the expression value is
`0(0-1)-5=-5`

if you put n=1 then the expression value is
`1(1-1)-5=-5`

if you put n=2 then the expression value is
`2(2-1)-5=-3`

if you put n=3 then the expression value is
`3(3-1)-5=1`