What is the slope of line a?

Given:
The graph of a line a.
To find:
The slope of the line a.
Solution:
Slope formula:
[tex]m=\dfrac{y_2-y_1}{x_2-x_1}[/tex]
From the given graph it is clear that the line a passes through the points (-1,1) and (0,-2). So, the slope of the line a is:
[tex]m=\dfrac{-2-1}{0-(-1)}[/tex]
[tex]m=\dfrac{-3}{1}[/tex]
[tex]m=-3[/tex]
The slope of the line a is -3. Therefore, the correct option is C.