Write the equation of the line passing through the given pair of points. (-9, 7) and (-9, -1)

The first thing I should do with these two points is find the slope of the line.

m = (y2 - y1)/(x2 - x1)

m = (-1 - 7)/(-9 - -9)
m = -8/0

The slope is undefined. We cannot divide by 0. This makes sense because the points (-9, 7) and (-9, -1) would be right on top of each other.  This is a vertical line that has an x-intercept at -9. 

Your equation would be x = -9.

An arithmetic sequence is a sequence where the difference between any two consecutive terms is a constant.

The constant between two consecutive terms is called the common difference.

The common difference is the number added to any one term of an arithmetic sequence that generates the subsequent term.

The terms of an arithmetic sequence can be found by beginning with the initial term and adding the common difference repeatedly.

Step-by-step explanation: