The slope-intercept form: y = mx + b
m - the slope
b - y-intercept
y-intercept is -2, therefore y = mx - 2.
The line throught the point (2;-4). Subtitute the coordinates to the equation of the line:
-4 = 2m - 2 |add 2 to both sides
2m = -2 |divide both sides by 2
m = -1
Answer: y = -x - 2