Parallel lines have the same slope, so since you want a line that is parallel to a line with slope -8, your line will also have slope -8.
The slope-intercept form of the equation of a line is
y = mx + b
where m is the slope, and b is the y-intercept.
You already know you have a slope of -8, so m = -8, and you have
y = -8x + b
Now you need to find the value of b.
Use the point you know and substitute it in for x and y, and solve for b.
y = -8x + b
Use x = -8, and y = 2.
2 = -8(-8) + b
2 = 64 + b
-62 = b
b = -62
Now replace b with -62.
y = -8x + b
y = -8x - 62
