The Air conditioner unit in the classroom uses 120 volts. it requires 2000 watts of usage on the average, and it stays on for 8 hours every day. Find out the Amps, Watt hrs/Day, Watts hrs/yr, Kilowatt Hrs/Yr and cost/Yr if the cost of elelctricity per kilowatt is $0.25

Step-by-step explanation:

P = IV

2000 W = I (120 V)

I = 16.7 A

P = E/t

P = (2000 W × 8 hr) / (1 day)

P = 16,000 W·hr/day

P = 16000 W·hr/day × (365 day / yr)

P = 5,840,000 W·hr/yr

P = 5,840,000 W·hr/yr × (1 kW / 1000 W)

P = 5840 kW·hr/yr

C = 5840 kW·hr/yr × (0.25 $/kW/hr)

C = $1460/yr

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15