I don't understand how the equation to find a=6.25 & a=9 is broken down. It doesn't show any steps

(7) A competitive, profit-maximizing firm uses two inputs a and b. Its production function is F(a, b) = a1/2 + b1/2. Its output sells for L.E.5 per unit. The price of input a is L.E.1 per unit. If the price of output rises to L.E.6 per unit but factor prices do not change. a. it will increase its purchases of factor a by 11/4 units. b. it will increase its purchases of factor a by 9/4 units. c. it will increase its purchases of factor a by 3/4 units. d. we need to know the price of factor b to be able to determine the change in demand for a. e. None of the above. Solution: The optimal use of factor a at P=5 P * MPa= W 5 * =a 2 =1 a*= 6.25 The optimal use of factor a at P=6 P * MPa= W 6 -a 2=1 a* = 9 11 Aa = 9 - 6.25 =