Question 548483
There is an infinite number of ways to express the equation for a line. There are different forms, most of which come in infinite varieties. Slope-intercept form is my favorite, because there is only one equation in slope intercept form for each line. It's the equation of the line that starts with "y= ...".
INTERCEPT
The y-intercept is the point where the line crosses the y-axis. (unless the line is a vertical line, with an equation of x=some number, the line will cross the y axis somewhere. The point where it crosses will have x=0, of course. The y value, called just intercept, is what you are after.
In your case, the point (0,-8) is the y-intercept, so the intercept value that you are looking for is -8.
SLOPE-INTERCEPT FORM
The slope-intercept form is often represented as {{{y=mx+b}}}, with {{{m}}} being the slope and {{{b}}} being the intercept.
SLOPE
The slope of the line is the change in y as x increases by 1. You can always calculate it by dividing. It's the difference in y values between two points, divided by the corresponding difference in x values. It is traditionally represented by the letter "m".
In your case, you could calculate 
{{{m=(-2-(-8))/(2-0)=(-2+8)/2=6/2=3}}}
Another option, would be to write the equation including the intercept found, but with the "m" still in it, as
{{{y=mx-8}}}
and then substitute the coordinates of point (2, -2) and solve for m:
{{{-2=m*2-8}}} ---> {{{-2+8=2m}}} ---> {{{6=2m}}} ---> {{{m=3}}}
No matter how you calculate the slope, your equation in slope-intercept form is
{{{y=3x-8}}}