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Algebra Level 1

2 5 × 2 7 2 10 × 2 3 × 3 0 = ? \large \dfrac{ \color{#20A900}2^{\color{#3D99F6}{5}}\times \color{#20A900} 2^{\color{#3D99F6}{7}}}{\color{#20A900} 2^{{\color{#3D99F6}{10}}}\times \color{#20A900} 2^{\color{#3D99F6}{3}}}\times \color{#69047E}{3^0} = \ ?

1 2 \dfrac{1}{2} 1 1 3 2 \dfrac{3}{2} 2 2

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8 solutions

By rule of adding and subtracting powers : a m × a n = a m + n a^m \times a^n = a^{m+n} and a m ÷ a n = a m n a^m \div a^n = a^{m-n} .

For the numerator, we have 2 5 × 2 7 = 2 5 + 7 = 2 12 2^5 \times 2^7 = 2^{5+ 7} = 2^{12} .

For the denominator, we have 2 10 × 2 3 = 2 10 + 3 = 2 13 2^{10} \times 2^3 = 2^{10+3} = 2^{13} .

So the 2 5 × 2 7 2 10 × 2 3 = 2 12 2 13 = 2 12 13 = 2 1 \frac{2^5 \times 2^7 }{2^{10}\times2^3} = \frac{2^{12}}{2^{13}} = 2^{12 - 13} = 2^{-1} .

Because a m = 1 a m a^{-m} = \frac1{a^m} and a 0 = 1 a^0 = 1 , we have 2 1 × 3 0 = 1 2 × 1 = 1 2 2^{-1} \times3^0 = \frac12 \times 1 = \frac12 .

That's helpful. Thanks

Ray Sim - 5 years, 6 months ago

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Is it now? Good for you

Paul Costello - 5 years ago

One half is what I said.

William Reed - 5 years, 2 months ago

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Well done fam

Paul Costello - 5 years ago

Really helpful 👏. Thanks I made a mistake at first try.. Lol 😂

Richard Omisore - 5 years, 3 months ago

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Not funny man. No emojis please

Paul Costello - 5 years ago

Trying these things for the first time, im stuggling to understand how 2 to the power of -1 x 3 = 1/2. Probably a stupid question but anyone feeling helpful?

Jim Gales - 4 years, 9 months ago

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Just in case someone else has the same problem, what you're looking for is 2^-1 x 3^0 which then becomes 2^-1 x 1, not 3

Sj Emmons - 4 years, 4 months ago

Really helpful, I appreciate you explaining this :)

Adrian Zermeño Rodríguez - 4 years, 4 months ago

Можно сократить 2^5 и 2^10 на 2 в числителе и знаменателе. Получим, 2^7/2^15 Числитель < знаменателя, значит результат будет 0.003...5, т.о. просто выбираем вариант 1/2

Jack Black - 3 years, 5 months ago

No one ever told me about a on -m. Thanks

Martina Jelen Smolko - 2 years, 2 months ago

Thanks I understand now

Cletus Ade - 11 months ago

Very helpful thank you

Emmanuel Ganaway - 4 months, 3 weeks ago

That's good...thank you...

Anwesha Sinha - 5 years ago
Cindy Wu
May 29, 2015

You need to know that x n × x m = x n + m x^{n} \times x^{m}=x^{n + m} x n x m = x n m \frac{x^{n}}{x^{m}}=x^{n - m} x n = 1 x n x^{-n}=\frac{1}{x^{n}} x 0 = 1 x^{0}=1 - this is true for any number, and pretty logical too - if 4 is 2x2 or 8/2 or 2^2, then 2 is 2x1 or 4/2 or 2^1, and 1 is 2x0.5 or 1/2 or 2^0

So, 2 5 × 2 7 = 2 5 + 7 = 2 12 2^{5} \times 2^{7}=2^{5 + 7}=2^{12}

And 2 10 × 2 3 = 2 10 + 3 = 2 13 2^{10} \times 2^{3}=2^{10 + 3}=2^{13}

Then 2 12 2 13 = 2 12 13 = 2 1 \frac{2^{12}}{2^{13}}=2^{12 - 13}=2^{-1}

2 1 = 1 2 1 = 1 2 2^{-1}=\frac{1}{2^{1}}=\frac{1}{2}

Since 3 0 = 1 3^{0}=1 it just stays as 1 2 \frac{1}{2}

x 0 x^0 is not true for 0. 0 0 0^0 is undefined

Gia Hoàng Phạm - 2 years, 8 months ago
Refath Bari
Jul 1, 2016

Let us first simplify ... 2 5 2 7 2 10 2 3 \frac { 2^{ 5 }*2^{ 7 } }{ 2^{ 10 }*2^{ 3 } }

using the Rule of Multiplying Exponents , as follows : 2 5 + 7 2 10 + 3 \frac { 2^{ 5+7 } }{ 2^{ 10+3 } } , which simplifies to: 2 12 2 13 \frac { 2^{ 12 } }{ 2^{ 13 } }

By the rule of dividing exponents, we must 2 12 13 2^{ 12-13 } , which we can simplify to the negative exponent: 2 1 2^{ -1 } , which becomes 1 2 { \frac { 1 }{ 2 } } .

Final Answer : 1 2 { \frac { 1 }{ 2 } }

Q E D Q\bullet E\bullet D

3°=1 is a revelation for me!

Athmanathan Seetharaman - 2 years, 5 months ago

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Me too. I got the rest, but I kept staring at 3° thinking "how can three multiplied by three zero times equal anything? Shouldn't the answer become zero?" Clearly I need to back up further and brush up on exponents.

Whisper Interstellar - 1 year, 5 months ago
Gia Hoàng Phạm
Sep 19, 2018

2 5 × 2 7 2 10 × 2 3 × 3 0 = 2 5 + 7 2 10 + 3 × 1 = 2 12 2 13 = 2 12 13 = 2 1 = 1 2 \frac{2^5 \times 2^7}{2^{10} \times 2^3} \times 3^0=\frac{2^{5+7}}{2^{10+3}} \times 1=\frac{2^{12}}{2^{13}}=2^{12-13}=2^{-1}=\frac{1}{2}

Mohammad Khaza
Jun 24, 2017

2^5x2^7x3^0/2^10x2^3

=2^12/2^13

=2^-1

=1/2. [ anything ^o=1]

Mxjd Ultimate
Jun 6, 2021

3^0 is 1. We can erase that. The numerator result is 2^12 and the denominator result is 2^13. Since 2^12 is 1/2 of 2^13, the answer is 1/2

Tom Wang
Jun 25, 2020

denominator is 2^12, numerator is 2^13, therefore giving 1/2

2 5 × 2 7 2 10 × 2 3 × 3 0 \frac{2^5 \times 2^7}{2^{10} \times 2^3} \times 3^0

Because a 0 = 1 a^0 = 1 , we have:

2 5 + 7 2 10 + 3 × 1 \frac{2^{5+7}}{2^{10+3}} \times 1

= 2 12 2 13 × 1 = \frac{2^{12}}{2^{13}} \times 1

= 2 0 2 1 × 1 = \frac{2^0}{2^1} \times 1

= 1 2 × 1 =\frac{1}{2} \times 1

= 1 2 = \frac{1}{2}

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