In order to find this, we first have to find the slope of the original line. We do this by solving for y.
3x + 4y = 20
4y = -3x + 20
y = -3/4x + 5
Now that we have the slope of -3/4 we can find the perpendicular slope. The perpendicular slope of any time is the opposite and reciprocal slope. So we flip -3/4 to get -4/3 and then we make it positive (4/3). Now that we have our new slope, we can input it along with the point into point-slope form to find the equation.
