Slope-intercept form: y = mx + b
(m is the slope, b is the y-intercept or the y value when x = 0 --> (0, y) or the point where the line crosses through the y-axis)
To find the slope (m), use the slope formula:
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex] And plug in the two points
(3, -8) = (x₁, y₁)
(6, -4) = (x₂, y₂)
[tex]m=\frac{-4-(-8)}{6-3}[/tex] (two negative signs cancel each other out and become positive)
[tex]m=\frac{-4+8}{6-3}[/tex]
[tex]m=\frac{4}{3}[/tex] Now that you know the slope, substitute/plug it into the equation
y = mx + b
[tex]y=\frac{4}{3} x+b[/tex] To find b, plug in either of the points into the equation, then isolate/get the variable "b" by itself. It doesn't matter which. I will use (3, -8)
[tex]-8=\frac{4}{3} (3)+b[/tex]
-8 = 4 + b Subtract 4 on both sides to get "b" by itself
-12 = b
[tex]y=\frac{4}{3}x-12[/tex]
