CHALLENGE: What is the value of k?

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CHALLENGE: What is the value of k?

by Brent@GMATPrepNow » Fri Dec 07, 2018 10:51 am

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What is the value of k?

$$(1) k^2-5k-66=0$$
$$(2) \frac{2k}{k^2+5k}=\frac{1}{8}$$

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by Iakgmat » Fri Dec 07, 2018 4:52 pm

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(1) yields (x+6)(x-11), which gives x=-6, 11
(2) yields k=11

So knowing (2) is sufficient.