You calculate it by taking the change in y's over the change in x's. So (y1-y2)/(x1-x2). You get the equation (-5 - 3)/(5 - 7) which equals 4. 4 is the slope.
If There is a math equation you can use math-way.
Also it would help if you can take a better picture.
Once you take a better picture I promise i will try my best to answer the question.
Answer:
4n -13
Step-by-step explanation:
notice that the difference between the adjacent terms is 4.
nth term is given by:
nth term = first term + (n-1) × difference -n is any number
= -9 + (n-1) × 4
= -9 + 4n -4
= 4n -13
The answer is 13
If R=4 the the equation would be 4+9 which equals 13.
The given inequality is:

This inequality can be divided in two parts as:
a)

b)

Solving part a:

Solving part b:

Therefore, the solution to the given inequality is

and

. Combining both the ranges we get the solution:

.
In interval notation, this solution can be expressed as [1,5]