Find a formula for an arithmetic sequence that begins 80, 83, 86, 89, ...​

= 3n + 77

Step-by-step explanation:

The nth term of an arithmetic sequence is

= a₁ + (n - 1)d

where a₁ is the first term and d the common difference

Here a₁ = 80 and d = a₂ - a₁ = 83 - 80 = 3 , then

= 80 + 3(n - 1) = 80 + 3n - 3 = 3n + 77

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!

it would rotate about 180 degrees.