# How do you find the formula for #a_n# for the arithmetic sequence #a_1=-y, d=5y#?

##### 1 Answer

Aug 26, 2017

#### Answer:

# u_n = (5n-6)y#

#### Explanation:

If we have

# {a,a+d,a+2d,...,a+(n-1)d}#

Assuming

# a = -y #

# d = 5y #

So the

# u_n = -y + (n-1)5y #

# \ \ \ \ = (5n-6)y#