We can use the slope formula to find the slope of AB, which is the same as the slope of the parallel line. Then, we can use the point-slope equation for a line to find the desired equation.
m = (y2 -y1)/(x2 -x1)
m = (-8 -2)/(-1 -4) = -10/-5 = 2
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y -y1 = m(x -x1) . . point-slope form of equation for a line
y -5 = 2(x -0) . . . . fill in m=2, (x1, y1) = (0, 5)
y = 2x +5 . . . . . . . rearrange to slope-intercept form