2^x - 2^x-2 = 3(2^13)
i think the problem is like this : 2^x - 2^(x-2) = 3(2^13)
-> 2^x - 2^x/4 = 3(2^13) (as 2^(a-b) can be written as 2^a / 2^b)
4* 2^x - 2^x = 3(2^13)*4
3*2^x = 3(2^13)*(2^2)
2^x = 2^(13+2) = 2^15
thus x=15
Exponent Problem
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cans
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cans
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2^(x-2) to (2^x)/4
lhs: (2^x)*(2^(-2)) = (2^x)/4
lhs: (2^x)*(2^(-2)) = (2^x)/4
If my post helped you- let me know by pushing the thanks button
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Cans!!
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GMATGuruNY
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Can's solution is great. For a less algebraic approach, check here:
https://www.beatthegmat.com/2-x-2-x-2-3- ... tml#309765
https://www.beatthegmat.com/2-x-2-x-2-3- ... tml#309765
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Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
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As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
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Abhishek009
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2^x - 2^x-2 = 3(2^13)alicia wrote:This was a problem on my practice test. Please advise on the step by step solution/breakdown for this problem:
If 2^x - 2^x-2 = 3(2^13), what is the value of x?
a. 9
b. 11
c. 13
d. 15
e. 17
The correct answer is d. 15
Or, 2^x - 2^x-2 = {(2^2) - 1}(2^13)
Or , 2^x - 2^x-2 = 2^15 -2^13
Now we can safely claim x = 15...
Abhishek
There can be only two options. 15 or 17 since rhs has 2^13alicia wrote:This was a problem on my practice test. Please advise on the step by step solution/breakdown for this problem:
If 2^x - 2^x-2 = 3(2^13), what is the value of x?
a. 9
b. 11
c. 13
d. 15
e. 17
The correct answer is d. 15
Now: (2^x - 2^(x-2))/ 2^13 = 3
Substitute 15: Answer will be 4-1 =3 Success!
