Find all complex numbers z such as z^4 = -4

should be in the form as a+bi

Ajar contains a mixture of 20 black marbles, 16 red marbles, and 4 white marbles, all the same size. find the probability of drawing a white or red marble on the first draw. 125 12 01 next question ask for turn it in

The john nash mall used 17,4000 kilowatt hours in may, with a peak load of 92 kilowatts. the demand charge is $5.95 per kilowatt, and the energy charge is $0.08 per kilowatt hour. the fuel adjustment charge is $0.017 per kilowatt hour. what is the total electricity cost for may?

You work for a landscape company that just got a contract to re-mulch a park. the area that needs mulching is 30 feet by 60 feet. they want a 3 inch layer of much on the area. the company has bags of mulch that cover 2 cubic yards that cost $4.00 per bag. how much will it cost the consumer just in materials to re-mulch the area (round to the nearest dollar)?