how do I solve both A and B?

Suppose that x and 3.! represent the amounts of two basic inputs for a production process and that the equation 30x2 {55:33.5 =12,548 describes all input amounts where the output of the process is 12,548 units. . d? a) Find 3' b] What is the marginal rate of substitution of x for y when x = 625 and y = 320