Use equation of line which passes through the 2 points [tex]A(x_1,y_1),B(x_2,y_2)[/tex].
[tex]y-y_1= \frac{y_2-y_1}{x_2-x_1}(x-x_1) \\ \\A(1,5),B(-2,3)
\\ y-5= \frac{3-5}{-2-1}(x-1)
\\y-5= \frac{2}{3} (x-1)
\\y-5=\frac{2}{3}x-\frac{2}{3}
\\3y-15=2x-2
\\-2x+3y=-2+15
\\-2x+3y=13[/tex]
