Explanation:
the point-slope form is
y - y1 = a(x - x1)
"a" being the slope, (x1, y1) being the point on the line.
y = ax + b
is the slope-intercept form of a line.
again, "a" is the slope.
a parallel line must have the same slope.
so, our equation is
y - 8 = -6(x - -6) = -6(x + 6)
y - 8 = -6(x + 6)