I don't understand the part inside the circle, how did it get to L=8

(2) The production function is given by F(L) = 612/3. Suppose that the cost per unit of labor is L.E.16 and the price of output is L.E.8. How many units of labor will the firm hire? P X MP = W a. 16 b. 8 8x ( 46 3 1 = 16 C. 4 32 L d. 24 SKUL 3 - 16 32 e. None of the above. 21 3 = 1 Solution: 32 x 3= 16 P * MPL= WL NNX N/ - -1 8 ( 6.~ x3) = 16 X 3 = ; L* = 8 ( = 2 3 2 8