N is a positive integer
(I) explain why n(n-1) must be an even number

(II) explain why 2n+1 must be an odd number

Answers

Answer 1

Part (1)

n is some positive integer. Let's say for now that n is even. So n = 2k, for some integer k

This means n-1 = 2k-1 is odd since subtracting 1 from an even number leads to an odd number.

Now multiply n with n-1 to get

n(n-1) = 2k(2k-1) = 2m

where m = k(2k-1) is an integer

The result 2m is even showing that n(n-1) is even

------------

Let's say that n is odd this time. That means n = 2k+1 for some integer k

And also n-1 = 2k+1-1 = 2k showing n-1 is even

Now multiply n and n-1

n(n-1) = (2k+1)(2k) = 2k(2k+1) = 2m

where m = k(2k+1) is an integer

We've shown that n(n-1) is even here as well.

------------

So overall, n(n-1) is even regardless if n is even or if n is odd.

Either n or n-1 will be even. If you multiply an even number with any number, the result will be even.

=======================================================

Part (2)

n is some positive integer

2n is always even since 2 is a factor of 2n

2n+1 is always odd because we're adding 1 to an even number. The sequence of integers goes even,odd,even,odd, etc and it does this forever.

-----------

Another way to see how 2n+1 is odd is to divide 2n+1 over 2 and you'll find that we get (2n+1)/2 = 2n/2+1/2 = n+0.5

The 0.5 at the end is not an integer, so there's no way that (2n+1)/2 is an integer; therefore 2n+1 is odd.


Related Questions

What two products would you add to find 713​x48

Answers

9514 1404 393

Answer:

  40·713 and 8·713

Step-by-step explanation:

When this multiplication is carried out "by hand", the usual sum of partial products is ...

  8·713 + 40·713

Answer:

5704, 28520

Step-by-step explanation:

First find the product of 713 x 48 which is 34224. Next, we find the two products to do so we first add 713 x 8 = 5704.Then,we multiply 713 x 40 which is 28520. This strategie is multiply by the ones then by the tens and add them together to find the your answer.

12.
Bharathi borrows an amount of 12500 al 12% per annum for 3 years at a simple inters
and Madhuri borrows the same amount for the same time period at 10% per annum
compounded annually. Who pays more interest and by how much?

Answers

Answer:

Step-by-step explanation

For bharathi

Principal,P =Rs 12500

Simple interest Rate,R = 12%

Time period,n = 3 years.

Simple Interest, SI at 12% for 3 years =

(12500×12×3)/100

= Rs 4500

For Madhuri

Principal,P =Rs 12500

Compound interest Rate,R = 10% p.a.

Time period,n = 3 years.

Amount when interest is compounded annually

C.i=A-P

C.i=(1+R/100)^3-p

=12500((1+10/100)^3-12500

=12500(11/10)^3-12500

=[(125×11×11×11)/10×10×10]-12500

=16637.50-12500

=4137.50

Bharathi pays more interest and Rs (4500 - 4137.50) = Rs 362.50 more.

The number of miles a car can drive varies directly with the number of gallons of gas in
the car. If the car can go 81 miles on 3 gallons of gas, how many gallons does the car
need to go 378 miles?

Answers

Answer:

14 gallons

Step-by-step explanation:

Answer:

14 gallons

Step-by-step explanation:

solve for z: -4 - (z - 6) = 12

Answers

Answer:

z = -10

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDASEquality Properties

Step-by-step explanation:

Step 1: Define equation

-4 - (z - 6) = 12

Step 2: Solve for z

Distribute negative:                              -4 - z + 6 = 12Combine like terms:                             -z + 2 = 12Subtract 2 on both sides:                    -z = 10Divide -1 on both sides:                        z = -10

Step 3: Check

Plug in z to verify it's a solution.

Substitute:                    -4 - (-10 - 6) = 12Subtract:                       -4 - (-16) = 12Simplify:                        -4 + 16 = 12Add:                               12 = 12

Here we see that 12 does indeed equal 12.

∴ z = -10 is a solution of the equation.

Answer:

z = -10

Step-by-step explanation:

-4 -(z+6)=12

2-z=12

-z =12-2

ans= z = -10

Solve for x in the following angle relationship. Please also identify the type of angles given:


answer options

O x= 10, corresponding

O x = 4, corresponding

O x = 10, alternate interior

O x = 4, Same side interior​

Answers

9514 1404 393

Answer:

  x= 10, corresponding

Step-by-step explanation:

Corresponding angles are in the same direction from their respective intersections. Here, the angles are both northwest of the point where the lines cross. The angles are corresponding.

__

Corresponding angles are congruent, so we have ...

  10x +10 = 110

  10x = 100 . . . . . subtract 10

  x = 10 . . . . . . . . divide by 10

Geena is meeting her brother at a cafe on Bradford Rd and Blanco Rd. She is currently on the corner of Lafayette Ave. and Blanco Rd.

Her brother tells Geena that the shortest route is straight down Blanco Rd.
Geena disagrees. She thinks the shortest route is down Lafayette Ave., turn onto Smith St., then on Blanco Rd. until she reaches the cafe.
Who is correct? What is the difference in the two routes?

Answers

Answer:

THEY ARE BOTH IN DIFFERENT PLACES??

Answer:

.25

Step-by-step explanation:

PLS ANSWER ASAP!!!!!
The temperature is dropping at a rate of 2.5 degrees for 4.25 hours. How much did the temperature change?
Group of answer choices

A.) -10.625 degrees

B.) -6.75 degrees

C.) 10.625 degrees

D.) 6.75 degrees

Answers

Answer:

A

Step-by-step explanation:

Answer:

The correct answer would be A.

Can someone plzz answer this!!?

Answers

Answer: B Angle Side Angle

Step-by-step explanation:

Since line AB and CD are parallel angles D and A are congruent by the alternate interior theorem and both angles AOB and DOC are congruent by the vertical angle theorem and it already shows line OC and line OB are congruent.

Find the value of all angles

Answers

Answer:

Step-by-step explanation:

This means that <C and <F are congruent.

So 2x - 15 = x + 15             Add 15 to both sides

2x-15+15=x+15+ 15

2x = x + 30                        Subtract x from both sides

2x-x=x-x+30

x = 30  

I've taken the bottom 2 angles to be equal. The lettering says they

are

4x - 3y = 13
8x - 6y = 26

Solve systems of equations through elimination method please!

Answers

Answer: 0 = 0

Many solutions

Step-by-step explanation:

4x - 3y = 13

8x - 6y = 26

-2(4x - 3y = 13)

-8x + 6y = -26

8x - 6y = 26

You can cross them all out and you’ll get 0 = 0 which also means many solutions

Given: 4d=1/3(c-d) Proof= c=13d

Answers

Proof:

Multiply both of the sides by 3. You would get 12d = c - d. Add d on both sides, and you would get c = 12d

Here, we are required to proof c = 13d from 4d=1/3(c-d)

Ultimately, c = 13d (proof)

We have;

4d=1/3(c-d)

Cross product

4d × 3 = c - d

therefore, By collecting like terms;

C = 12d +d

and Ultimately, c = 13d ......

Read more:

https://brainly.com/question/21406377

HELP ASAPPP!!! !!!! PLEASE

Answers

Answer:

B.

Step-by-step explanation:

for decimals, you start with tenths, so it would be thousandths

The answer is A. Because it is in the thousands

HELP ASAP PLS AND THANKS!!!!

Answers

The first one is the correct answer

Answer:

The first one

23·4 1 6 +37·4 1 6 HOW DO I DO THIS?!?!?

Answers

Answer

60.832

Step-by-step explanation:

Combine the numbers

HOPE THIS HELPS YOU....

Joshua uses his thermometer and finds the boiling point of ethyl alcohol to be 75o C. He looks in a reference book and finds that the actual boiling point of ethyl alcohol is 80oC. What is his percent error?

Answers

Answer:

the percent error is 6.25%

Step-by-step explanation:

The computation of the percent error is shown below:

Percent error is

= (Experimental value - accepted value) ÷ (experimental value) × 100

= (80 degrees - 75 degrees) ÷ (80 degrees) × 100

= (5 degrees) ÷ (80 degrees) × 100

= 0.0625 × 100

= 6.25%

hence, the percent error is 6.25%

We simply applied the above formula so that the correct value could come

And, the same is to be considered

Answer:

6.25

Step-by-step explanation:

I just did this

Brainliest!! Pls help

Answers

Answer:

its c

Step-by-step explanation:

that one is shaded down other one is shaded up (up = greater)( down= less)

Yeah it is letter c it is the correct answer

The total bill at a restaurant was $52.50. If you want to tip the waitress 15%, how much tip should you leave?
A. $7.87
B. $7.88
C. $78.70
D. $78.75

Answers

Answer:

B

Step-by-step explanation:

52.50*0.15=7.875

7.875 rounded is 7.88

hope this helps :3

if it did pls mark brainliest

Answer:

B)$7.88

Step-by-step explanation:

15% = 0.15

52.50 x 0.15 = 7.875

Round to the nearest hundredth

$7.88

question is in the picture ​

Answers

Answer: d,f

[tex]-x\geq 4\\=> x\leq -4[/tex]

=> all the values are d and f

Step-by-step explanation:

(-4, 12) and (-7, -3)

(Write an equation of the line in point slope form that passes through the giving points)

Answers

Answer:

5

Step-by-step explanation:

Use the slope formula: [tex]\frac{y_2-y_1}{x_2-x_1}[/tex]

[tex]\frac{-3-12}{-7-(-4)}[/tex] = [tex]\frac{-15}{-3}[/tex] = 5

3f+7=1
Plz write explanation

Answers

Answer:

f = -2

Step-by-step explanation:

3f + 7 = 1

or, 3f = 1 - 7

or, 3f = -6

or, f = -6/3

or, f = -2

True or False: A function must have a different output for each input.

Answers

Answer:

True

Step-by-step explanation:

for every X there can be on Y

that doesn't necessarily go the other way around, but that's not what the problem is asking, so whatever.

Nathan goes to the store and buys 4 shorts and 3 shirts for 85.5$. He later goes to the same store and buys 3 shorts and 5 shirts for 115$. What is the price for each shirt and each shorts?

Answers

4x+3y=85.5
3x+5y=115
Combine it
X=7.5 y=18.5

cAn SOmeOnE PLeAse HELp ME WIth Math

Answers

Answer: B

Step-by-step explanation:

I did this last year so I can recall how to solve it :p

(barely)

Adelaide has a credit card with a company that charges $3.00 for every day a payment is late. If she paid $492.93 for a bill that is 3 days late, how much was the bill without the late fee?

Answers

The answer is $483.93 just subtract $9 from 492.93


Which one should I choose

Answers

Answer:

Third one

C.

Step-by-step explanation:

Evaluate the expression when a=14 and b=6. 5b/32a2

Answers

Answer:

28/16071  as a decimal 0.00174226...

Step-by-step explanation:

Hope this helps!

Help please!! If you can't see the photo well just let me know <3​

Answers

Answer: The second one and fourth one.      

Step-by-step explanation: did this already and got it right :)

Crystal bought b boxes of cookies to bring to a party. Each box contains 18 cookies. She decides to keep two boxes for herself. She brings 90 cookies to the party. Which equation can be used to find the number of b boxes Crystal bought?
A) 2b − 18 = 90
B) 18b − 2 = 90
C) 18b − 36 = 90
D) 36 − 18b = 90

Answers

Answer:b

Step-by-step explanation:

she took 2 boxes and there is 18 per box 18 times b = 90

The answer is b I know this because I did it

Question 1 of 10
Which of Saturn's moons has an atmosphere that is most like Earth's?
O A. Pandora
B. Atlas
Ο Ο
C. Titan
O
D. Europa
SUBMIT

Answers

I’m pretty sure it’s C. Titan

Answer:

The answer is Titan

Step-by-step explanation: the atmosphere of Titan is similar to earth's atmosphere because Titan's atmosphere is mostly made up of nitrogen and so is Earth's atmosphere.

If you ever see a cheetah coming to you Don’t PANIC it should be going up to you very fast get ready and when it comes pound it in the chest and get up on your toes and act to be tall and the cheetah will be scared of you and shoutout to evansandre2007 and vc538720 for my 1st and 2nd Friends add me and thank me For more

Answers

Answer:

you would have to be still!

Step-by-step explanation:

What bro where am i gon encounter a cheetah bruh
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