To find the equation of a line, in point-slope form, that represents a line with m = -12/13 that goes through the point (21,0), we must know what point-slope form is. Point-slope form is y - y₁ = m(x-x₁), with (x₁, y₁) being the coordinates of the point. Now, since we have all of the information that we need, we can substitute the values of the things that we know.
y - 0 = -12/13(x - 21)