Question

What is the 12th term of the sequence 5, 12, 19....?

Answer 1

82

Explanation:

The Sequence equation is: Tn=7n-2
T12th=7x12-2

T=TERM
N=Which term( 1st,2nd,3rd)
the sequence is going up in seven's and you wouldn't want to start with 7 for the equation so how do you get from 7 to 5? Subtract 2.
Then for a term you're trying to find just add it into the sequence equation. Practice this!

Answer 2

`82`

Explanation:

We observe that difference between first and second terms `=12-5=7`
Similarly difference between second and third terms `=19-12=7`

It shows that the given sequence of numbers is an arithmetic progression with common difference equal to `7`.

We know that `nth` term of an AP whose first term is `a_1` and whose common difference is `d` is given by
`a_n = a_1 + (n – 1) d`

To find the `12th` term, insert given values in the general expression
`a_12 = 5 + (12 – 1) 7`
`a_12 = 5 + (11) 7=5+77=82`