Can't see the 3 for the forest

Algebra Level 2

2 × 3 12344 2 \times 3^{12344} 3 12344 3^{12344} 3 × 3 12345 3 \times 3^{12345} 3 12345 3^{12345}

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32 solutions

Abhiram Kumar
Oct 8, 2014

3^12345 - 3^12344 = 3*(3^12344) - 3^12344.

Taking 3^12344 as a common factor,

3^12344 (3-1) = 2 (3^12344)

Let x = 3^(12344). We know that 3^12345 = 3 * 3^(12344), thus let 3^(12345) = 3x. 3x - x = 2x = 2 * 3^(12344)

Corey Cooper - 6 years, 8 months ago

i don't understand the solution

Dev Rajput - 6 years, 8 months ago

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in the expression
3^12345-3^12344
we can factor out 3^12344 so,
3^12344(3^1-1)
the answer is 2(3^12344)..

Christian Rogales - 6 years, 7 months ago

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Thanks, now I know.

Chris Schinke - 5 years, 7 months ago

Lol neither do I and I love exposants.

Chris Schinke - 5 years, 7 months ago

3^12345 - 3^12344 =3^12344 x3 - 3^12344=3^12344(3-1)=2x3^12344

Amarjeet Sharma - 6 years, 8 months ago

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Easy method to solve this problem. Thanks my frnd

Ajit Borah - 5 years, 10 months ago

Good Work Abhiram Kumar, you are a very smart smart boy- Kevin Tran HAHS Australia sydney 15

kevin gay - 6 years, 7 months ago

i dont understand this problem plz anyone explain me.

Ragini Jadhav - 6 years, 8 months ago

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let n=12344 so 3^12344 =3^n in question we have 3^12345 - 3^12344 so it becomes 3^n+1-3^n look this carefully (3^n) ((3)^1)-3^n now taking common (3^n) so 3^n((3)^1-1) it becomes 3^n(3-1) 3^n(2) 2 3^n as n=12344 2*3^12344

Sohaib Mudassar - 6 years, 8 months ago

u take common from both term and then u should get (3-1) it gives u 2 , and u multiply by common term

Kurdia Gaurav - 6 years, 8 months ago

re- write it down on a paper as abhiram kumar solved it.

کاظم آغا - 6 years, 8 months ago

We can able to write 3^12345 as 3^(12344+1) We know that X^(a+b) that's equal to (X^a)(X^b) Here X is 3, a is 12345 and b is 1 then we will get 3^(12344+1) as (3^12344)(3^1) Substitute this in original question , then we will get, ((3^12344)(3))-(3^12344) By taking common outside 3^12344(3-1) Then the answer is (3^12344)2

Kannan Sachin - 5 years, 10 months ago

u r great...............!

Sohaib Mudassar - 6 years, 8 months ago

… use this formula that i was derived ., (x^(n+a)) - (x^(n)) = (x^(a) -1)(x^(n)) ., where x: is the base ., n: the value of exponent ., a: is the difference between the exponent of the first term to the second term,

Since 12345-12344=1 ., so a=1 ., x=3 ., n=12344 ..

Then;

3^(1234+1) - 3(12344) = (3^(1) - 1)(3^(12344)) 3^(12345) - 3(12344) = (2)(3^(12344))

HEHEHE ^_^ ..

Kian UnZe - 6 years, 8 months ago

:( i dont understand

maryam gardezi - 6 years, 8 months ago

Good question.....

Shraddha Bung - 6 years, 8 months ago

Explain me clearly

Vijayalakshmi Lakshmi - 5 years, 10 months ago

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We can able to write 3^12345 as 3^(12344+1) We know that X^(a+b) that's equal to (X^a) (X^b) Here X is 3, a is 12345 and b is 1 then we will get 3^(12344+1) as (3^12344) (3^1) Substitute this in original question , then we will get, ((3^12344) (3))-(3^12344) By taking common outside 3^12344(3-1) Then the answer is (3^12344) 2

Kannan Sachin - 5 years, 10 months ago

It also works in the general case of (3^n)-(3^n-1) = 2*(3^n-1)

Charles Rand - 5 years, 8 months ago

3^12345(3-1)

Punit Shukla - 6 years, 8 months ago

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wrong because you have to take common just 3^12344

Shoaib Shoaib - 6 years, 8 months ago

not in multiplication of (3-1) in power of three,, its the simply multiplication

Pradeep Kumar Sahoo - 6 years, 8 months ago

how bcome 3-1?

joriz villariza - 6 years, 8 months ago

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after taking the common 3^12344

Aporajita Tume - 6 years, 8 months ago

I am a gay man, sucking on bananas. I am Kevin Tran, 15 y.o gay, living in Sydney Australia, Goes to Hurlstone Agricultural High School Glenfield, 10th grade, asian boy.

Kevin Gay2 - 6 years, 7 months ago
Ryan Choco
Oct 12, 2014

If one is looking for a more logical and visual explanation, you could simply say that 3^12345 is 3 groupings of 3^12344, and that by subtracting 3^12344, you are merely taking away one of the 3 groupings, meaning what is left behind are 2 of these grouping, therefore the answer is 2 * 3^12344

thank you for the simplified explanation. you really make it easy.

Deepraj Drake - 6 years, 8 months ago

Nice explanation...you made it easy for me

Allan Lindo - 6 years, 7 months ago

Are you a teacher! You should be😊

Ashley Martin - 5 years, 11 months ago
Adam Blakey
Oct 12, 2014

3 12345 3^{12345} is going to be 3 times the size of 3 12344 3^{12344} . If we say x = 3 12344 x = 3^{12344} , we can then write the initial equation as 3 x x 3x - x , which, of course, is going to be 2 x 2x . So the answer is 2 3 12344 2 * 3^{12344} .

Wim Borsboom
Oct 12, 2014

I did this to figure it out: 3^3 - 3^2 = 27-9 = 18 = 2 9 = 2 3^2 thus by analogy, the answer must be (and of course is):
2 * 3^12344

that's a nice way.

Nehal Arifen - 6 years, 8 months ago

The answer by Wim Borsboom has been wrongly typed. =18 = 29 should have been 2*9 Shashi thatte.

Shashikant Thatte - 6 years, 8 months ago

Exactly the way that I solved it ;-)

Gordon Glenn - 6 years, 8 months ago

I thought no one would do this method, but someone did!!!!!

Raakin Kabir - 4 years, 11 months ago

I did it that way too! I just couldn't think straight with all the bigger exponents.

Maureen Kimball - 4 years, 9 months ago
Joshua Ong
Oct 22, 2014

3 12345 3 12344 = 3^{12345}-3^{12344}= 3 ( 3 12344 ) 3 12344 = 3(3^{12344})-3^{12344}= 3 12344 + 3 12344 + 3 12344 3 12344 = 3^{12344}+3^{12344}+3^{12344}-3^{12344}= 3 12344 × 2 \boxed{3^{12344}\times2}

Md Omur Faruque
Jul 12, 2015

Taking 12344 12344 as x x , let's rewrite the expression as, 3 x + 1 3 x 3^{x+1}-3^{x} = 3. 3 x 3 x =3.3^{x}-3^{x} = 2. 3 x =2.3^{x} = 2 × 3 12344 =\boxed{2\times3^{12344}}

Shadi Barghash
Oct 12, 2014

Let y = 3^12345 - 3^12344 so y is the answer we want to get.

We want to do something to eliminate one of the 3^..., so what about dividing both sides by 3^12344?

So we now have: (3^12345)/(3^12344) - (3^12344)/(3^12344) = y / (3^12344)

The first term, can be written as 3^(12345-12344), right? That is equal to 3^1 = 3.

For the second term, the upper and lower sides of the fractions are equal which easily shows the fraction is equal to ONE, and that what we wanted (to see less 3^... in the left side).

Now, you have: 3 - 1 = y / (3^12344) 2 = y / (3^12344)

Here, you can cross-multiply to make "y" the subject, which will result in.. y = 2 * 3^12344

Yay!! It's actually one of the choices, and it's an easier way to represent the answer. :D

Satyam Dahiwal
Aug 13, 2015

Let 3 12345 3 12344 = x 3^{12345}-3^{12344}=x

Dividing both sides by 3 12344 3^{12344} , we get

3 12345 3 12344 3 12344 3 12344 = x 3 12344 \frac{3^{12345}}{3^{12344}} - \frac{3^{12344}}{3^{12344}} = \frac{x}{3^{12344}}

3 1 = x 3 12344 3-1=\frac{x}{3^{12344}}

x = 2 × 3 12344 x=2×3^{12344}

3^12345-3^12344=3^12344(3-1)
thus, the answer is 2 * (3^12344)

let 3^12345 =3 X

let 3^12344 =X

3X-X=2X

X = 3^12344

→ 2X = 2*3^12344

Niaz Ghumro
Oct 11, 2014

3^12345 - 3^12344 = 3(3^12344) - 3^12344. By taking 3^12344 as common we get 3^12344(3-1) = 2*(3^12344).

please elaborate

maryam gardezi - 6 years, 8 months ago
Michael Mele
Dec 1, 2016

They had this same question yesterday

Anwesha Sinha
Jun 22, 2016

We have 3^12345-3^12344

We can take 3^12344 as common

Now, we get

3^12344 (3-1)

2×(3^12344)

Adriel Padernal
Oct 4, 2015

My exponent theorem @ https://brilliant.org/discussions/thread/exponent-theorem-10 states that b n b n 1 = b n 1 ( b 1 ) b^n - b^{n-1} = b^{n-1} (b-1) .

By substitution,

3 12345 3 12345 1 = 3 12345 1 ( 3 1 ) 3^{12345} - 3^{12345-1} = 3^{12345-1} (3-1)

3 12345 3 12344 = 3 12344 × 2 3^{12345} - 3^{12344} = 3^{12344} \times 2

3 12345 3 12344 = 2 × 3 1234 \boxed{3^{12345} - 3^{12344} = 2 \times 3^{1234}}

Asok Kumar
Sep 6, 2015

3raise to 12344(3-1)=2x3raise to 12344

Lukas Leibfried
Aug 3, 2015

3^12345 - 3^12344 = 3^(12344+1) - 3^12344 = (3 ^ 1 - 1) x 3^12344 = 2 x 3^12344

Shubham Kumar
Jul 13, 2015

3^12345-3^12344=3^12344 (3^1-1)=2*3^12344

Ayran Michelin
Jul 12, 2015

The first one (3^12345) is 3 times bigger than the another one (3^12344).

So if u Subtract (3^12344) just one time from (3^12345) than u get not more 3 x (3^12344), but just 2 x (3^12344).

Yasser Tawfik
Jun 12, 2015

3^12344(3-1)=3^12344*2

Which means we took 3^12344 as coomon term then remaining equal to 3 minus 1 which equal 2*3^12344

I don't know, I just guessed it

Jared Lindsey
May 11, 2015

left of commodity acquired given rides by rate..the compiled form is more than equity it quantifes by numeric exponential base...of fact direct of angle above by equality..by even there is a spread.… not iconified

Muhammad Sayed
Apr 21, 2015

Just simplify the equation into 3^2 - 3^1 = 9 - 3 = 6 ... where 6 actually equals 2 * 3^1 ..

Repeat using 3^12344 instead of 3^1 :)

Jack Han
Jan 22, 2015

3^{n+1} - 3^n=3^n (3-1)=2 \cdot 3^n \n=12344 \ \therefore 3^{12345} - 3^{12344}= 2 \cdot 3^{12344}

Ariella Lee
Oct 28, 2014

3 12345 3 12344 3^{12345}-3^{12344}

Factor out 2 12344 2^{12344} .

3 12344 ( 3 12345 3 12344 3 12344 3 12344 ) = 3 12344 ( 3 1 ) = 3 12344 ( 2 ) 3^{12344} ( \frac{3^{12345}}{3^{12344}}-\frac{3^{12344}}{3^{12344}})\\=3^{12344}(3-1)\\=3^{12344}(2)

= 2 × 3 12344 =\boxed{2\times3^{12344}}

Tasnim Rizvy
Oct 17, 2014

a^n - a^(n-1) = a^n - a^n.a^-1 = a^n . (1 - 1/a ) = a^n . (a-1)/a = (a^n)/a . (a-1) = (a^(n-1)) (a-1) If a=3 & n=12345 3^12345 – 3^12344 = 2 . 3^12344

Keshav Gupta
Oct 16, 2014

LIKE 3^3 - 3^2 27-9 =18 NOW 18 ,and we write that 2x3^2 same as 2x3^12344

Anisur Anis
Oct 14, 2014

3^12344 x3- 3^12344 =3^12344(3-1) =2X3^12344

Logically, if you look at them closely, none of the other three options are mathematically possible. 2x3^12344 is the only possible answer. Not a very mathematical solution maybe but the 'process of elimination' is easy here.

Anil Patel
Oct 12, 2014

3^12345-3^12345=3^(12344+1)-3^12344=3 3^12344-3^12344 taking 3^12344 common....... 3^12344(3-1)=2 3^12344 (Ans.) .

Thirupathi Gudala
Oct 12, 2014

3^12345-3^1234 =3^1234(3-1) =3^1234(2)

Joe Klovance
Oct 12, 2014

3^12345 -3^12344 = 3x3^12344 -1x3^12344) = (3-1)x3^12344= 2x3^12344

Yohan Gadde
Oct 12, 2014

3^12344(3-1) = 2 3^12344 , ( 3^12344 3^1)-3^12344 = 3^12344(3-1) 3^12344 2 2 3^12344

3^12345-3^12344=3^12344(3^1-3^0)=3^12344(3-1)=3^12344(2)=2*3^12344. in such case 3^1=3 and 3^0=1 that

shakir ibrar - 6 years, 7 months ago

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