How do you consider these lines?

Question

Line 1: Passes through (-4,9) and (-5,9) 

Line 2: Passes through (5,8) and (5,-14)

The slope of Line 1 is    

The slope of Line 2 is     

Consider the following two lines. 

Line 1: Passes through (-6,-5) and (-6,10) 

Line 2: Passes through (1,-2) and (1,1)

The slope of Line 1 is     

The slope of Line 2 is    

Consider the following two lines. 

Line 1: Passes through (6,-1) and (2,1) 

Line 2: Passes through (-3,-5) and (0,3)

The slope of Line 1 is  

The slope of Line 2 is  

Answer 1

This is just point slop form. The slope of a line, m, is just the change in y over the change in x

so for the first example

Line 1: Passes through (-4,9) and (-5,9) 

change in y = 9-9 = 0

change in x = -5 - -4 = -9

m = zero, this is a vertical line

Line 2: Passes through (5,8) and (5,-14)

change in y is -14 - 5 = -19

change in x is 5-5 = 0

m = 0, this is a horizontal line

repeat for the other two problems