Which of the following differential equations have x^2-4y^2=8 as a solution? a) dy/dx = 4xy
b) dy/dx = 4x/y
c) y dy/dx = x/4
d) dy/dx = -x/4y

Herbert company gathered the following information on its mixed power costs and factory machine usage for the last four months: month power costs factory machine hours january $ 24,400 13,900 february $ 30,000 17,000 march $ 29,000 16,800 april $ 14,000 7,000 if it is estimated that 10,000 factory machine hours will be used in the month of may, what is the expected total power costs for may?