Hi Lindsey;
(1, 5) and (3, 5)
Slope is the changeofy divided by changeofx...
m=(yy_{1})/(xx_{1})
Either point can be denoted as _{1}.
m=(55)/(13)
m=0/4
The change of y is zero. It is a straight, horizontal line.
Answer B
If the change of x is zero, it would be a straight, vertical line with an undefined slope because zero cannot be a denominator/divisor.
Jan 24

Vivian L.