Consider the following production function: 9 = 9LK + 5L2 - (3) 13 Given the following expressions for the marginal productivity of each input: MP, = 9K + 10L - Land MPK - 9L re 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 = 20 and L = 15. (Round your answer up to two decimal places and include the proper sign.) MRTS = SSI on 1 on 5 Istic on 9 stic ion 1 stio