Question

Find an equation for the nth term of the arithmetic sequence.

-20, -16, -12, -8, ...

Answer 1

its an 'arithmetic sequence',
so lets find the common-difference first :)

Answer 2

okay

Answer 3

plus 4

Answer 4

Yes !

Answer 5

common-difference \(d = 4\)

Answer 6

see that, first term \(a = -20\)

Answer 7

ok

Answer 8

simply plug those in the 'nth term of arithmetic sequence formula' :)
do u have the formula in ur notes ?

Answer 9

here is the formula :-
\(\large a_n = a+ (n-1)d\)

Answer 10

plugin a & d values we found before

Answer 11

kk

Answer 12

an=20+(n-1)4

Answer 13

\(\large a_n=\color{red}{-}20+(n-1) \times 4\)

Answer 14

an = -20 + 4(n - 1)

Answer 15

u forgot the negative sign before 20, otherwise it looks good :)

Answer 16

looks good :)

Answer 17

or an = -20 x 4(n - 1)

Answer 18

its just

an = -20 + 4(n - 1)

Answer 19

thank you!!

Answer 20

np :)