Make sure to show all work and box all final answers$\mathrm{.}1)$ Fishs Fun Factory produces swimming toys. Let x represent the number of dolphin toysproduced each week and let y represent the number of shark toys produced each week. Theweekly cost, in dollars, is given by $(,)=620\mathrm{.}3400.$It should be noted that the first order partial derivatives are: $(,)=60\mathrm{.}3$ and $(,)=20\mathrm{.}3$Use the appropriate partial derivative to find the marginal cost of producing shark toys$($approximate change in cost when producing one more shark toy$)$ at a production level of $15$dolphins and $23$ sharks? Express your answer using appropriate units$\mathrm{.}2)$ Consider the function $(,)=.$Find all critical points of $(,)$ and classify them using the Second Derivative Test. Provide yourfinal answer as an ordered triple $(,,)\mathrm{.}3)$ Maximize $(,)=3$ subject to the constraint $2=36$ using Lagrange Multipliers.Provide your final answer as an ordered triple $(,,).($Note: You can use the substitution method to check your work, but you will only receive full