Any tips on how to solve this?
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What is y in terms of x?
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fourteenstix
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theCodeToGMAT
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fourteenstix
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GMATGuruNY
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Plug in a value for x and solve for y.fourteenstix wrote:
Let x=3, so that 5^(x-3) = 5� =1.
Plugging x=3 into the equation, we get:
5³ - 5� = 124 * 5^y
124 = 124 * 5^y
1 = 5^y
y=0.
Since the question stem asks for the value of y, our target is y=0.
Now plug x=3 into the answers to see which yields our target of 0.
A quick scan of the answer choices shows that only C works:
x-3 = 3-3 = 0.
The correct answer is C.
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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.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
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theCodeToGMAT
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The same rule by which we say:fourteenstix wrote:How did you get from:
5^x - 5^(x-3) = 5^(3+y) - 5^y
to:
x-3=y
by "comparing both sides"?
5^x = 5^2 so x=2
the difference is just that we have similar structure on LHS & RHS but with "-" sign.. so compare the powers.
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