Respuesta :
We want to find the equation of the line that passes through the points:
(4 , -8) and (9 , 11)
First, we're going to find the slope between these points using the fact that:
If we have two points that lie on a line:
[tex](x_1,y_1)\text{ and }(x_2,y_2)[/tex]The slope between them can be found using the formula:
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]If we replace our values:
[tex]\begin{gathered} (x_1,y_1)=(4,-8) \\ (x_2,y_2)=(9,11) \\ x_1=4 \\ x_2=9 \\ y_1=-8 \\ y_2=11 \end{gathered}[/tex]The slope will be:
[tex]m=\frac{11-(-8)}{9-4}=\frac{11+8}{5}=\frac{19}{5}[/tex]Now, we could apply the point-slope equation. This equation tells us that we can find the equation of the line if we got a point (x1,y1) on the line, and the slope m:
[tex]y=y_1+m(x-x_1)[/tex]Replacing our values:
[tex]\begin{gathered} y=-8+\frac{19}{5}(x-4) \\ y=-8+\frac{19}{5}x-\frac{76}{5} \\ y=\frac{19}{5}x-\frac{116}{5} \end{gathered}[/tex]This, is the general form. We want to express the last equation as a standard form like this:
[tex]Ax+By=C[/tex]If we re-write:
[tex]\begin{gathered} y=\frac{19x-116}{5} \\ \\ 5y=19x-116 \\ 19x-5y=116 \end{gathered}[/tex]Therefore, the standard for the equation of the line that passes through (4 , -8) and (9, 11) is:
19x-5y=116
