We can calculate the slope of a line segment by using the formula:
[tex]m=\frac{y2-y1}{x2-x1}[/tex]
Where (x1,y1) and (x2,y2) are two points of the line.
In this case the side DF goes from the point D(-2,-2) to the point F(1,7), then its slope is:
[tex]m=\frac{7-(-2)}{1-(-2)}=\frac{7+2}{1+2}=\frac{9}{3}=3[/tex]
For the side, CD, it goes from D(-2,-2) to C(0,4), then its slope is:
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