Given,
[tex]P_1(13,2)[/tex]
[tex]P_2(9,1)[/tex]
[tex]P_3(x,-3)[/tex]
Formula:
[tex]m= \frac{y_2-y_1}{x_2-x_1} [/tex]
solution:
First get the slope from [tex]P_1[/tex] to [tex]P_2[/tex]
[tex]m= \frac{1-2}{9-13} [/tex]
[tex]m= \frac{1}{4} [/tex]
then, solve for the x:
[tex]m= \frac{-3-1}{x-9} [/tex]
[tex]\frac{1}{4}= \frac{-3-1}{x-9} [/tex]
[tex]x-9=4(-3-1)[/tex]
[tex]x=-7[/tex]
checking
[tex]\frac{y_2-y_1}{x_2-x_1}=\frac{y_3-y_2}{x_3-x_2}[/tex]
[tex] \frac{1}{4} = \frac{-3-1}{-7-9} [/tex]
[tex] \frac{1}{4} = \frac{1}{4} [/tex]
