Use the following slope-intercept form of a line equation:
y = mx + b
Where m is the slope of the line and b the value of y when x=0 (it is also the y-intercept).
To find the slope m, use the following formula:
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]where (x1,y1) and (x2,y2) are any pair of points on the line.
For instance, use:
(x1,y1) = (-4,-8)
(x2,y2) = (8,4)
[tex]m=\frac{4-(-8)}{8-(-4)}=\frac{4+8}{8+4}=\frac{12}{12}=1[/tex]You can notice, based on the graph, that y = -4 for x = 0. Then, the y-intercept is b = -4.
Then, by replacing the values of m and b into the slope-intercept formula, you get:
y = x - 4 (this equation represents the line)
