Subtracting Big Powers

Algebra Level 1

6 2007 6 2006 30 = ? \large \frac {\color{#D61F06}6^{\color{#3D99F6}{2007}} - \color{#D61F06}6^{\color{#3D99F6}{2006}}}{\color{#20A900}{30}} = \ ?

0.2 0.2 30 30 36 36 6 2005 6^{2005} 6 2007 6^{2007}

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15 solutions

6 2007 6 2006 30 = 6 2006 ( 6 1 ) 30 = 6 2006 5 30 = 6 2006 6 = 6 2005 \large \dfrac{6^{2007} - 6^{2006}}{30} = \dfrac{6^{2006} (6 - 1)}{30} = \dfrac{6^{2006} \cdot 5}{30} = \dfrac{6^{2006}}{6} = 6^{2005}

This is a very clear explanation

Aritri Samaddar - 5 years, 6 months ago

Where does the 6-1 come from?

WolvenChaos Anonymous - 5 years, 2 months ago

Log in to reply

Factorization

rafael fodor - 5 years, 2 months ago

6^2006 is taken common from both 6^2006 & 6^2007. 6^2007 is obviously 6x of 6^2006. Thats why 6^2007-6^2006 is converted to 6^2006 (6-1). If you solve multiply the bracket as given i.e. (6^2006×6)-(6^2006×1) you will get the same numbers given in example.

Mandar Bhide - 5 years, 1 month ago

I did it that way too

Evan Huynh - 5 years, 5 months ago

Nice. it's simple solution

K.Pushpa priya - 2 years, 5 months ago

It’s wrong

James Huffaker - 1 year, 8 months ago
Leonardo Sipayung
Mar 27, 2015

1st step we can change 6 2007 6^{2007} to become : 6 2006 × 6 6^{2006} \times 6 so, 6 2006 ( 6 ) 6 2006 30 \frac {6^{2006}(6) - 6^{2006}}{30} 6 2006 ( 6 1 ) 30 \frac {6^{2006} (6-1)}{30} 6 2006 ( 5 ) 30 \frac {6^{2006}(5)}{30} 6 2005 ( 5 ) ( 6 ) 30 \frac {6^{2005}(5)(6)}{30} 6 2005 ( 30 ) 30 = 6 2005 \frac {6^{2005}(30)}{30} = 6^{2005}

your solution made me get the (6-1) everyone else was using. nice step by step solution!

Christelle Solajo - 6 years, 2 months ago

Where's the 6-1 coming from?

WolvenChaos Anonymous - 5 years, 2 months ago
Lucas Mayol
Mar 25, 2015

My way :

6 2007 = 6 × 6 2006 6^{2007} = 6 \times 6^{2006}

So:

6 2007 6 2006 = 6 × 6 2006 6 2006 = 5 × 6 2006 6^{2007} -6^{2006} = 6 \times 6^{2006} - 6^{2006} = 5 \times 6 ^{2006}

And:

6 2006 = 6 × 6 2005 6 ^{2006} = 6 \times 6^{2005}

Now is easy:

6 2007 6 2006 = 5 × 6 × 6 2005 = 30 × 6 2005 6^{2007} -6^{2006} = 5 \times 6 \times 6^{2005} = 30 \times 6^{2005}

6 2007 6 2006 30 = 30 30 × 6 2005 = 6 2005 \frac{6^{2007} -6^{2006}}{30} = \frac{30}{30} \times 6^{2005} = 6^{2005}

Oh! Now I get it. Thanks. <3

Martina Valla - 5 years, 2 months ago

Thank you so much. This took me an hour studying the logic you use to get that results. The" 6×6^2006 - 6^2006= 5×6^2006" made no sense whatsoever until it click in my brain. Very helepful.

Darkdro 47 - 3 years, 1 month ago
Seán Vaeth
Apr 29, 2015

The trick is solving the behavior in the numerator first. Consider the problem with smaller numbers:

6 3 6 2 = 216 36 = 180 6^{3} - 6^{2} = 216 - 36 = 180 Here we see that if we did 6 cubed minus 6 squared we would get 6 cubed - 36 (makes sense because 6^3 = 6 * 6 = 36 * 6) Recall 6 * 36 = 36 + 36 + 36 +36 + 36 + 36 So what we have done essentially is subtracted one term from the final number This gives us the following equation 6 3 6 2 = 6 2 5 o r ( 6 1 ) 6^{3} - 6^{2} = 6^{2}*5 or (6 - 1)

Now that we solved a trivial example, we can apply it to all cases. 6 2007 6 2006 30 = 6 2006 ( 6 1 ) 30 = 6 2006 5 30 \frac{6^{2007}-6^{2006}}{30} = \frac{6^{2006} * (6 - 1)}{30} = \frac{6^{2006}*5}{30} = 5 30 6 2006 = 6 2006 6 / / r e d u c e t h e f r a c t i o n = \frac{5}{30} *6^{2006} = \frac{6^{2006}}{6} - //reduce-the-fraction 6 2006 6 = 6 2006 6 1 = 6 2006 1 = 6 2005 / / L a w s o f e x p o n e n t i a l m a t h \frac{6^{2006}}{6} = \frac{6^{2006}}{6^{1}} = 6^{2006-1} = 6^{2005}//Laws-of-exponential-math

This process of problem solving is known as induction and can be used to solve most solutions by finding a pattern in smaller trivial cases

Yuvraj Bind
Mar 26, 2015

6^(2007)- 6^(2006)/30
= 6^(2006) (6-1)/30
= 6^(2006)
5/30
= 6^(2006)/6
= 6^(2005)


Aravind Vishnu
Mar 28, 2015

6 2007 6 2006 30 = 6 2005 × 6 ( 6 1 ) 30 = 6 2005 × 30 30 = 6 2005 \frac{6^{2007}-6^{2006}}{30}=\frac{6^{2005} \times 6(6-1)}{30}\\ =\frac{6^{2005}\times 30}{30}\\ =6^{2005}

I was doing a freaking mess with logaritms for at least one hour when I realized everything.

6 2007 6 2006 30 = . . . \frac{6^{2007}-6^{2006}}{30}=... . . . = 6 ( 6 2006 ) 6 2006 30 = . . . ...=\frac{6(6^{2006})-6^{2006}}{30}=... . . . = 5 ( 6 2006 ) 30 = 6 2006 6 = . . . ...=\frac{5(6^{2006})}{30}=\frac{6^{2006}}{6}=... . . . = 6 2005 ...=6^{2005}

James Moors
Mar 24, 2015

6 2007 6 2006 30 = 5 6 2006 5 6 = 6 2005 \frac{6^{2007}-6^{2006}}{30} = \frac{5 \cdot 6^{2006}}{5\cdot 6} = 6^{2005}

(6^2007-6^2006)/30=(6*6^2006-6^2006)/30={6^2006(6-1)}/30=(6^2006 *5)/30=6^2006/6=6^2005

Saúl Huerta
Sep 9, 2019

What I did was to first simplify the fraction:

6 2007 6 2006 6 5 \frac{6^{2007}-6^{2006}}{6\cdot5} = = 6 2006 6 2005 5 \frac{6^{2006}-6^{2005}}{5}

Then I started thinking about ways to solve this problem and instead of factorizing I observed a pattern in the differences of the powers of 6 6 :

6 2 6 = 30 6^2-6=\boxed{30}

6 3 6 2 = 180 6^3-6^2=\boxed{180}

6 4 6 3 = 1080 6^4-6^3=\boxed{1080}

6 5 6 4 = 6480 6^5-6^4=\boxed{6480}

. . . ...

As you can see the difference of two consecutive powers of 6 6 increases by a factor of six as the degrees increase by one:

30 , 180 , 1080 , 6480 , . . . 30, 180, 1080, 6480, ...

And I realized that the first equation was just the multiplication 6 5 = 30 6\cdot5=30 and if I applied this concept to the other equations it would be as follows:

6 3 6 2 = 6 2 5 6^3-6^2=6^2\cdot5

6 4 6 3 = 6 3 5 6^4-6^3=6^3\cdot5

6 5 6 4 = 6 4 5 6^5-6^4=6^4\cdot5

6 x + 1 6 x = 6 x 5 6^{x+1}-6^x=6^x\cdot5

So now we substitute x x :

6 2006 6 2005 5 \frac{6^{2006}-6^{2005}}{5} = = 6 2005 5 5 \frac{6^{2005}\cdot5}{5}

6 2005 5 5 \frac{6^{2005}\cdot5}{5} = 6 2005 =\boxed{6^{2005}}

Gandoff Tan
Apr 7, 2019

6 2007 6 2006 30 = 6 2006 6 6 2006 30 = 6 2006 ( 6 1 ) 30 = 5 ( 6 2006 ) 5 6 = 6 2006 6 = 6 2005 \begin{aligned} \frac { { 6 }^{ 2007 }-{ 6 }^{ 2006 } }{ 30 } & = & \frac { { 6 }^{ 2006 }\cdot 6-{ 6 }^{ 2006 } }{ 30 } \\ \quad & = & \frac { { 6 }^{ 2006 }(6-1) }{ 30 } \\ \quad & = & \frac { 5({ 6 }^{ 2006 }) }{ 5\cdot 6 } \\ \quad & = & \frac { { 6 }^{ 2006 } }{ 6 } \\ \quad & = & \boxed { { 6 }^{ 2005 } } \end{aligned}

Gia Hoàng Phạm
Sep 19, 2018

6 2007 6 2006 30 = 6 2006 ( 6 1 ) 30 = 6 2006 × 5 30 = 6 2006 6 = 6 2006 1 = 6 2005 \frac{6^{2007}-6^{2006}}{30}=\frac{6^{2006}(6 - 1)}{30}=\frac{6^{2006} \times 5}{30}=\frac{6^{2006}}{6}=6^{2006-1}=\boxed{\large{6^{2005}}}

6 2007 6 2006 30 \frac{6^{2007} - 6^{2006}}{30} = 6 2006 ( 6 1 ) 30 \frac{6^{2006}(6 - 1)}{30} = 6 2006 5 30 \frac{6^{2006} \cdot 5}{30} = 6 2 006 6 \frac{6^2006}{6} = 6 2005 6^{2005}

Peter Michael
May 30, 2017

Common factor top

Reduce the quotient to show

Six to the power 2005

Anwesha Sinha
Jun 16, 2016

We can take 6^(2006) as a common

value..i.e,

6^(2006)(6-1)/30

Now, we can solve it as..

6^(2006)×5/30

After solving further,we get

6^(2006)/6

which equals to 6^(2005)

which is the answer.

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