What is the slope of the line that passes through the points (1, -6)(1,−6) and (-8, 9) ?(−8,9)?

The answer to your question is  m = -5/3      

Step-by-step explanation:

Data

Point 1 = (1, -6)

Point 2 = (-8, 9)

Process

To find the slope just substitute the values in the formula and simplify.

Formula

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

-Identify x1, y1, x2 and y2

  x1 = 1    y1 = -6   x2 = -8  y2 = 9

-Substitution

             m = (9 + 6) / (-8 - 1)

-Simplification

             m = 15/-9

-Result

             m = -5/3            

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value