Kiersten runs a website that people learn programming. every month, kiersten receives a subscription fee of \$10$10dollar sign, 10 from each of the subscribers to her website. last month, the website had 100100100 subscribers. this month, 303030 new members joined the website, and 101010 members cancelled their subscription.
how much money will kiersten’s online business earn this month?
\$

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb

can you add an image ?

step-by-step explanation: