How can I solve this question? Please explain it for me.

1. The weekly cost (in dollars) for a business which produces x e-scooters and y e-bikes (per week!) is given by: z = C(x,y) = 80000 + 3000x + 2000y - 0.2xy a) Compute the marginal cost of manufacturing e-scooters at a production level of 10 e-scooters and 20- e-bikes. b) Compute the marginal cost of manufacturing e-bikes at a production level of 10 e-scooters and 20-e- bikes. c) Find the z-intercept (for the surface given by z = C(x,y)) and interpret its meaning. 2. Given g(x,y,z) = x2y32-2 + 5xexyz3 - 100, a) find gxy = b) find azz c) evaluate gxy (1,0, 1) = azg a) evaluate 272 (1,0,1)