it would be great with clear steps and explanation thank you

A company manufactures 2 models of MP3 players. Let x represent the number (in millions) of the first model made, and let y represent the number (in millions) of the second model made. The company's revenue can be modeled by the equation R(I, y) = 180x + 190y - 3x2 - 4y - ry Find the marginal revenue equations RI(I, y) = 180 -9r - y X Ry(x, y) = 190-16y - I X We can achieve maximum revenue when both partial derivatives are equal to zero. Set RX = 0 and Ry = 0 and solve as a system of equations to the find the production levels that will maximize revenue. Revenue will be maximized when: 2690 X = 143 X y = 10.69930 X