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If x = 2^7^4 - 2^7^0, what is the largest
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29 Aug 2018, 06:53
29 Aug 2018, 06:53
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35% (00:31) wrong based on 40 sessions
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If \(x = 2^7^4 - 2^7^0\), what is the largest prime factor of x?
A)2
B)3
C)5
D)7
E)11
src:orbit test prep
A)2
B)3
C)5
D)7
E)11
src:orbit test prep
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Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: If x = 2^7^4 - 2^7^0, what is the largest
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29 Aug 2018, 07:19
29 Aug 2018, 07:19
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amorphous wrote:
If \(x = 2^7^4 - 2^7^0\), what is the largest prime factor of x?
A)2
B)3
C)5
D)7
E)11
A)2
B)3
C)5
D)7
E)11
Given: x = 2^74 - 2^70
Factor 2^70 from right side to get: x = 2^70(2^4 - 1)
Evaluate to get: x = 2^70(16 - 1)
Simplify to get: x = (2^70)(15)
Factor 15 to get: x = (2^70)(3)(5)
So, there are 3 different prime factors: 2, 3 and 5
The greatest prime is 5
Answer: C
Cheers,
Brent
Re: If x = 2^7^4 - 2^7^0, what is the largest
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07 Sep 2018, 19:44
07 Sep 2018, 19:44
amorphous wrote:
If \(x = 2^7^4 - 2^7^0\), what is the largest prime factor of x?
A)2
B)3
C)5
D)7
E)11
src:orbit test prep
A)2
B)3
C)5
D)7
E)11
src:orbit test prep
Given,
\(x = 2^7^4 - 2^7^0\)
\(x= 2^{70}(2^4 - 1)\)
\(x = 2^{70} 15\)
\(x = 2^{70}*5*3.\)
So, 5 is the largest prime of x.
The best answer is C.
