What's N if: 8 to the n power is over 8 to the 7th power?

Find the solutions to the quadratic equation below by completing the square. x2 - 8x - 7 = 0

Furkat [3]

Answer:

x=4- $\sqrt{23}$ , x=4+ $\sqrt{23}$

Step-by-step explanation:

(x^2-8x+16)-16-7=0

(x-4)^2=23

x=4- $\sqrt{23}$ , x=4+ $\sqrt{23}$

3 0

3 years ago

In May you used 900 kilowatt-hours of energy for electricity.

Sloan [31]

Answer:

a) "The total electrical energy use was 3,240,000,000 joules."

b) "The average power use is 1210 watts."

c)

Part 1: "To generate the electricity you used, 810 L is needed."

Part 2: "To generate the electricity you used, 214.00 gal is needed."

Step-by-step explanation:

a)

1 kilowatt-hours = $3.6x10^6$ joules

Converting 900 kilowatt-hours to joules, we have:

$900*(3.6*10^6)=3.24*10^9$ joules, or

Total Electrical Energy use = 3,240,000,000 joules

"The total electrical energy use was 3,240,000,000 joules."

b)

The month of May has 31 days and 1 day is 24 hours. So May has:

31*24=744 hours

Now, we divide 900 kW-hr by the number of hours in the month (744 hrs) to get average power use:

$\frac{900}{744}=1.21$ kW. Since 1000 Watts = 1 kW, we multiply this by 1000 to get the answer in Watts:

1.21 * 1000 = 1210 Watts

"The average power use is 1210 watts."

c)

Part 1:

The conversion efficiency of most generating stations is 33%. So we need to multiply the total electrical energy use (in joules) by a factor of 3 to get the amount of joules required. So:

(3.24 * 10^9)*3 = 9.72 * 10^9 joules

We divide this by 12 million joules to get the number of liters:

$\frac{9.72*10^9}{12*10^6}=810$

So, 810 liters is needed

"To generate the electricity you used, 810 L is needed."

Part 2:

We know that 0.2642 gallons is equal to 1 liters. To get the number of gallons needed, we multiply 810 by 0.2642. So:

810 * 0.2642 = 214.00 gallons

"To generate the electricity you used, 214.00 gal is needed."

7 0

3 years ago

Find the exact length of the curve. x = 9 + 9t2, y = 6 + 6t3, 0 ≤ t ≤ 4

andrew11 [14]

ANSWER

$=102 \sqrt{ 17}$

EXPLANATION

The equation of the curve is:

$x = 9 + 9 {t}^{2}$

$y = 6 + 6 {t}^{3}$

We differentiate to obtain:

$\frac{dx}{dt} = 18t$

$\frac{dy}{dt} = 18t$

The length of the arc

$l = \int _0 ^{4} \sqrt{ {( \frac{dx}{dt} )}^{2} + {( \frac{dy}{dt} )}^{2} } dt$

This implies that:

$= \int _0 ^{4} \sqrt{ {( 18t )}^{2} + {( {18 {t}^{2} } )}^{2} } dt$

$= \int _0 ^{4} 18t \sqrt{ 1+ { {18 {t}^{2} } }} dt$

$=102 \sqrt{ 17}$

3 0

3 years ago

Can someone please help me with my calc homework? Anyone who is good at Radical Expressions pls help.

Lesechka [4]

1. x
2. x
3. -x^2
4.
5. x
6. x^3
7. x
8. |x|
9. x-2
10. x/3
11. x/2
12. x+2

3 0

3 years ago

8 1/5 + 4 2/5 i need to know cus i dont understand it

inessss [21]

Answer:

63/5 or 12 (3/5)

Step-by-step explanation:

It is 8 whole (1 ÷ 5) plus 4 whole (2 ÷ 5)

So,we can write it as 8 (1/5) + 4 (2/5)

Then we will take those mixed fractions to improper fractions by using the rule of multiplication.

8 will be multiplied by 5 and then the value will be added to 1. Same rule will be applied for the second fraction.

(41÷5) + (22÷5)

Now we will take L.C.M. (Least common multiple) for both denominators 5 and 5. The L.C.M of 5 and 5 = 5

(41 + 22)/5

= 63/5

It is the answer. Also we can make this improper fraction into mixed fraction by dividing the whole number by 5.

12 (3/5)

6 0

3 years ago