The equation of a line that passes through two points is given by:
[tex]y-y_1=\frac{y_2-y_1}{x_2-x_1}(x-x_1)[/tex]
Plugging the values of the points given we have that:
[tex]\begin{gathered} y-(-21)=\frac{-3-(-21)}{-2-2}(x-2) \\ y+21=\frac{18}{-4}(x-2) \\ y+21=-\frac{9}{2}(x-2) \\ y+21=-\frac{9}{2}x+9 \\ y=-\frac{9}{2}x+9-21 \\ y=-\frac{9}{2}x-12 \end{gathered}[/tex]
Therefore the equation of the line is:
[tex]y=-\frac{9}{2}x-12[/tex]
