To find the slope of a line given two points, you should use the formula, [tex]Slope= \frac{ y_{2}-y_{1} }{ x_{2}- x_{1}}
[/tex].
In this exercise is given the coordinates of two points and it is asked to find the slope of a line which intercepts both points, which are (-7,3) and (1,-9). To find the slope, you should substitute the given coordinates into the previous mention formula.
[tex]Slope= \frac{ y_{2}-y_{1} }{ x_{2}- x_{1}} [/tex]
[tex]Slope= \frac{(3--9)}{(-7-1)} [/tex]
[tex]Slope= \frac{12}{-8} [/tex]
[tex]Slope=-1.5[/tex]
The slope of the line which passes through the coordinates (-7,3) and (1,9) is [tex] \frac{-6}{4} [/tex] or -1.5.
