Grad of 3y = 4x - 1 y = \(\frac{4x}{3}\) - \(\frac{1}{3}\) Grad = \(\frac{4}{3}\) Grad of Ky = x + 3 y = \(\frac{\text{x}}{\text{k}}\) + \(\frac{3}{4}\) Grad = \(\frac{1}{\text{k}}\) Since the two lines are perpendicular, \(\frac{1}{\text{k}}\) = -\(\frac{3}{4}\) -3k = 4 k = -\(\frac{4}{3}\)