The first term of an arithmetic sequence is 12. The 9th term is -20. What is the common difference of the arithmetic sequence?

-4

Step-by-step explanation:

The formula of an arithmetic sequence is nth term=a+(n-1)d. First term is a and common difference is d.

Let's plug our info in.

-20=12+(9-1)d

-20=12+8d

Subtract 12 from both sides.

-32=8d

Divide both sides by 8.

d=-4

Have a wonderful day! :D

(2,20) means that the 2 is 2 hours and 20 is 20$. so there both 20$ for 2 hours only the same price. like it says. so, the dunk tank and the bounce house are the same price (20$) for the same amount of time (2 hours).

hope i