when working with slope from 2 points .How do you find the slope of the line through each pair . For example: (15,-8),(8,-15)

Step-by-step explanation:

This assume we have a straight line.  

The slope of a line is the change in y corresponding to a change in x.  That, is, slope tells us how much y will change every time x changes by 1 unit.  E.g., a slope of 2 means that if we increase x by 1, y will increase by 2.

This means if we have two points, we can calculate the slope for a straight line.  Slope is often referred to as the "Rise/Run."  

Take the two given points and calculate both the Rise and the Run:

(8,-15) and (15,-5).

Going from left to right, from x = 8 to 15:

Rise = (-5-(-15)) = 10

Run = (15 - 8) = 7

Slope:  Rise/Run = 10/7

The slope is (10/7)

See the attachment for an example, assuming we have a line that is:

y = (10/7) + b

We aren't given the value of b, the y-intercept, but we can calculate it by entering one of the two points in the y=(10/7)x + b equation and solve for b.  I'll use point (15,-5):

y = (10/7) + b

-5 = (10/7)(15) + b

b = -(185/7)

y = (10/7)x - (185/7)