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What is the formula for the following arithmetic sequence?

12, 6, 0, -6, ...


an = 12 + (-6)( n - 1)
an = 12 + 6( n - 1)
an = -6 + 12( n - 1)
an = 6 + 12( n - 1)

and also what would be the 30th term?

Respuesta :

[tex]a_{n}[/tex] = 12 + (- 6)(n - 1 )

This is an arithmetic sequence with n th term

[tex]a_{n}[/tex] = [tex]a_{1}[/tex] + (n - 1)d

here d = - 6 - 0 = 0 - 6 = 6 - 12 = -6 and [tex]a_{1}[/tex] = 12, hence

[tex]a_{n}[/tex] = 12 + (- 6)(n - 1)

use this formula to find the 30 th term

[tex]a_{30}[/tex] = 12 + (- 6 × 29) = 12 - 174 = - 162



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