Consider the following production function: q = 7LK + 5L^2 - (1/3) L^3. Given the following expressions for the marginal productivity of each input: MP_L = 7K + 10L - L^2 and MP_K = 7L Assuming capital is plotted on the vertical axis and labor is plotted on the horizontal axis, determine the value of the marginal rate of technical substitution when K = 30 and L = 15. (Round your answer up to two decimal places and include the proper sign.)