If the starting number is 30 and the rule is "minus five", what is the formula and what is the 20th number in the sequence?

an = 30 -5(n-1)  OR   an   = 35 - 5n

a20 =   -65

Step-by-step explanation:

The formula for an arithmetic sequence is

an =a1 +d(n-1)

where a1 is the first term

d is the common difference

n is the term number

Substituting what we know

an = 30 -5(n-1)

We can rewrite this by distributing the 5

an = 30 -5n +5

     = 35 - 5n

The 20th term is n=20

a20 = 30 - 5(20-1)

       = 30 -5(19)          

      = 30 - 95

      = -65

the slope of the first function is -3. (3/1)

the slope of the second function is 1. (13-10/6-3).

since |-3| is greater than |1|, the function with the steepest slope is the first.

n=9

step-by-step explanation:

7 times a number = 7n

decreased by 13 = 7n-13

same as is =

5 times the number = 5n

increased by 5 = 5n+5

7n-13 = 5n+5

2n=18

n=9