You know the slope formula is:
[tex]m = \frac{y_2-y_1}{x_2-x_1} [/tex]
Plug in all the given information:
[tex] \frac{1}{7} = \frac{-1 - (-2)}{p-4}[/tex]
Simplify:
[tex] \frac{1}{7} = \frac{1}{p-4} [/tex]
Solve for p:
[tex] \frac{1}{7} (p-4) = 1[/tex]
[tex]p-4 = \frac{1}{ \frac{1}{7} } [/tex]
Use the reciprocal property, and subtract 4:
[tex]p = 1 *7 - 4[/tex]
[tex]p = 7-4=3[/tex]
There's your answer: p = 3. If any step doesn't make sense, then feel free to tell me!
