A 120 watt light-bulb is a 0.120 kilowatt light bulb.
In one hour, it uses 0.120 kilowatt-hour of energy.
If electrical energy costs $0.20 per kilowatt hour, then that light bulb costs
(0.120 kilowatt-hour / hour) x (0.20 dollar / kilowatt-hour) =
(0.120 x $0.20 / hour) =
$0.024 / hour = <span>2.4¢ per hour </span>
Answer:
d. 6
Step-by-step explanation:
BD = 2x-4
But it's also BE - CE + CD
BE is 3x-1
CE is 2x-3
CD is 2
so
BD = 3x-1 -(2x-3) +2
simplified
BD = 1x +4
since BD = BD (obviously), we can also say that the righthand sides of the two equation must be equal
2x -4 = 1x +4
let's solve for x and that put it into either of the 2 equations.
2x -4 = 1x +4
subtract 1x on both sides
x -4 = 4
add 4 on both sides
x = 8
substitute x for its value in 2x -4 = 1x +4
(this way we double check BD in two expressions at once. the equation should come out true, meaning same value for BD in each expression. both sides should be equal).
2*8 -4 = 1*8 +4
12 = 12
seems true
BD is safely 12
Answer:
Step-by-step explanation:
x + y = 25 ...........................(1)
{4x + 2y =64} / 2 divide the equation by 2
2x + y = 32 ........................(3)
Step Two
subtract (1) from (3)
2x + y = 32
x + y = 25
x = 7
Therefore from equation 1 we get x + y = 25
but x = 7
7 + y = 25 Subtract 7 from both sides.
y = 25 - 7
y = 18
Check
4*x + 2*y = 64
4*7 + 2*18 =? 64
28 + 36 = ? 64
64 = 64
The checks out to be the right answer.
