3. Suppose that the production function for a phone is Q ZOKG-jLo-j. The marginal product of labour is INK/L) \"-5, and the marginal product of capital is I0(L/K)\"5. Suppose that labour can be hired for $6 and the capital can be hired for $9. (20 pts.) a. When the rm is producing 49 units at lowest cost, what will the rm's marginal rate of technical substitution be? (5 pts.) b. Solve for the lowest-cost combination of labour and capital that will allow the rm to produce 49 phones. Fractional units of labour and capital are allowed (10 pts) c. What is the minimum cost of producing 49 phones? (5 pts.)