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nydimaria [60]
3 years ago
14

Evaluate. 2^n -1, where n =7​

Mathematics
1 answer:
sineoko [7]3 years ago
6 0

Step-by-step explanation:

Sub n in the equation

2^7-1 = 128-1=127

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Solve the system of linear equations using multiplication.
Anna71 [15]

Answer:

(8,-1)

Step-by-step explanation:

The given system is:

3x+3y=21

6x+12y=36

Since I prefer to use smaller numbers I'm going to divide both sides of the first equation by 3 and both sides of the equation equation by 6.

This gives me the system:

x+y=7

x+2y=6

We could solve the first equation for x and replace the second x with that.

Let's do that.

x+y=7

Subtract y on both sides:

x=7-y

So we are replacing the second x in the second equation with (7-y) which gives us:

(7-y)+2y=6

7-y+2y=6

7+y=6

y=6-7

y=-1

Now recall the first equation we arranged so that x was the subject. I'm referring to x=7-y.

We can now find x given that y=-1 using the equation x=7-y.

Let's do that.

x=7-y with y=-1:

x=7-(-1)

x=7+1

x=8

So the solution is (8,-1).

We can check this point by plugging it into both equations.

If both equations render true for that point, then we have verify the solution.

Let's try it.

3x+3y=21 with (x,y)=(8,-1):

3(8)+3(-1)=21

24+(-3)=21

21=21 is a true equation so the "solution" looks promising still.

6x+12y=36 with (x,y)=(8,-1):

6(8)+12(-1)=36

48+(-12)=36

36=36 is also true so the solution has been verified since both equations render true for that point.

5 0
3 years ago
Read 2 more answers
A press release describing the 1986 nonstop, round-the-world trip by the aircraft voyager including the following data:
adoni [48]

Answer:

a.) the average speed of the aircraft in miles per hour

115.76 miles/ hour

b.) the fuel consumption in miles per pound of fuel

(assume a density of 0.70 g/mL for the fuel.)

2.8 miles/Ib of fuel

Step-by-step explanation:

A press release describing the 1986 nonstop, round-the-world trip by the aircraft voyager including the following data:

flight distance: 25,012 miles

flight time: 9 days, 3 min., 44 seconds

fuel capacity: nearly 9000 lbs.

fuel remaining at the end of flight: 14 gal.

To the maximum number of significant figure permitted, calculate:

a.) the average speed of the aircraft in miles per hour

Step 1

We convert the time to hours

flight time: 9 days, 3 min., 44 seconds

1 day = 24 hours

9 days =

24 × 9

= 216 hours

60 mins = 1 hour

3 mins =

3/60 = 1/20 = 0.05 hours

1 hour = 60 minutes

1 minute = 60 seconds

1 hour = 60 × 60 = 3600 seconds

If 3600 seconds = 1 hour

44 seconds =

= 44/3600

= 0.0122222222 hours

Total number of hours spent = (216 + 0.05 + 0.0122222222) hours

= 216.06222222 hours

Speed = Distance/Time

= flight distance: 25,012 miles

Speed = 25,012 miles/ 216.06222222hours

= 115.76294895 miles/ hour

Approximately = 115.76 miles/ hour

b.) the fuel consumption in miles per pound of fuel

(assume a density of 0.70 g/mL for the fuel.)

Step 1

We determine how much fuel is used

We have 14 gallons of fuel left over

1 gallon = 3.785 litres

14 gallons =

Cross Multiply

14 gallons × 3.785 liters/1 gallon

= 52.9958 liters

Note that density of fuel =

0.70 g/ml

1 gram / millilitre = 1 kilogram / litre

Hence, 0.7g/ml = 0.7 kg/L

Hence,the mass of fuel left = 52.9958 liters * 0.7 = 37.09706kg

1 kilogram = 2.205 pounds

37.09706kg =

37.09706kg × 2.205 pounds

= 81.7990173 lbs

Since the full capacity = 9000 lbs

The fuel used = 9000 - 81.7990173 lbs

= 8918.2009827 lbs

Hence, fuel consumption is

Distance/ amount of fuel used

25012/8918.2009827 lbs = 2.8046015164 miles/lb of fuel

Approximately = 2.8 miles/Ib of fuel

7 0
3 years ago
I need help with this
Lisa [10]

Answer:

1

Step-by-step explanation:

15,580.84 rounded to the nearest 10 thousand is 20,000

8 0
3 years ago
PLEASE HELP IMAGE BELOW
gtnhenbr [62]

Answer:

Q1) ans-16%

Q2) ans-50%

Q3) ans- 16%

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5 0
2 years ago
If one supplementary angle measure 51 degrees the other angle measures 39 degrees?
mojhsa [17]
The answer to your question is false
7 0
3 years ago
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