Perpendicular lines have opposite, reciprocal slopes. I'll show you 2 ways to solve.
y - (-4) = (-1/2)(x - 8) y + 4 = (-1/2)x + 4 y = (-1/2)x
orrrr...
-4 = (-1/2)(8) + b -4 = -4 + b b = 0
Well, we don't write "+ 0" because that's just extra work.
y = (-1/2)x
Note if you see an equation like this, know that b (our y-intercept) is 0. If you see something like y = 7, then the slope is 0, but 0 times our x-value would equal 0 and that's also unnecessary.
