How to Find the Explicit Formula of an Arithmetic Sequence

[@DawnsOfficial]

Thank you so much, I literally have a test today and what my teacher has been teaching makes no sense to me so thank you

[@midnightmathtutor3597]

I’m so glad it helped! Good luck on your test! 🤞🤞

[@hazelnut2.8]

you are so helpful thank you so much

[@midnightmathtutor3597]

Happy to help!

[@Callofdutybestgamer]

Hi. Just want to know how did it become 9n -2 where did the 2 come from can u explain plz i have an final exam tmr

[@midnightmathtutor3597]

Good question! When we plug it into the equation, we get 7 + 9(n - 1) this is the explicit formula, and some people may prefer to leave it this way. If you want to get rid of the parenthesis, you distribute the 9 in (if you need a review on the distributive property you can watch this: kzbin.info/www/bejne/l4OagqurrZuChtk) and it becomes 7 + 9n - 9 . When you do 7 - 9, you get -2, so you end up with 9n -2. Hope that helps! (I explain it around 2:43)

[@Callofdutybestgamer]

@ THANK YOU SO MUCH HELPFULLLL 💚💚💚💚💚💚💚💚💚

[@midnightmathtutor3597]

@Callofdutybestgamer you’re welcome!

[@farmphs2]

Can you help me please? My teacher gave me different things and she never explained it to us , she gave me just this a1=-8 an= 30 n=15

[@alina-pc4yh]

search up khan academy practices or something

[@midnightmathtutor3597]

Without seeing the exact problem, I can't know for sure, but I can do my best guess! a with the subscript 1 should mean the first number in the sequence. My guess would be the a sub n = 30 and n = 15 mean that the 15th term in the sequence is 30. Or it could mean they want you to figure out what the 15th number in the sequence is. The part that is throwing me off is the a sub n = 30...Was there any other info given?

[@MsVsayz]

Im sorry but u just brushed over this "distribute " part. Why did that happen? And how will i knkw when to do tnat in a problem? What type of problems require that step?!?!?!

[@midnightmathtutor3597]

Good question! The distributive property helps us to simplify equations. When we have something like (x - 5), we can't subtract those because they aren't like terms. But, if there is something on the outside, the distributive property tells us we can multiply it in. So 2(x - 5) becomes 2x - 10. This video may help explain it a little better: kzbin.info/www/bejne/l4OagqurrZuChtk

[@JanySins-p7e]

wo finally tysm

[@midnightmathtutor3597]

You’re welcome! Thanks for letting me know it was helpful!