The slope of horizontal line y = a (a - any real number) is equal 0.
Answer: the slope is equal 0.
Proof:
The formula of a slope:
[tex]m=\dfrac{y_2-y_1}{x_2-x_1}[/tex]
We have two points (look at the picture) (0, 2) and (7, 2). Substitute:
[tex]m=\dfrac{2-2}{7-0}=\dfrac{0}{7}=0[/tex]
