If \(π‘π‘žπ‘Ÿ β‰  0\) and \(𝑝^{βˆ’π‘₯} = \frac {1} {π‘ž} , π‘ž ^{βˆ’π‘¦} = \frac {1} {π‘Ÿ}…

2018

IfΒ \(π‘π‘žπ‘Ÿ β‰  0\) and \(𝑝^{βˆ’π‘₯} = \frac {1} {π‘ž} , π‘ž ^{βˆ’π‘¦} = \frac {1} {π‘Ÿ} , π‘Ÿ^{βˆ’π‘§} = \frac {1} {𝑝 }\), what is the value of the product \(π‘₯𝑦𝑧\)Β ?

  1. A.

    \(βˆ’1\)

  2. B.

    \(\frac {1} {pqr}\)

  3. C.

    \(1\)

  4. D.

    \(π‘π‘žπ‘Ÿ\)

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Correct answer: C

Given p^{-x} = 1/q, q^{-y} = 1/r, r^{-z} = 1/p and pqr β‰  0.

  • Invert each equation to remove negative exponents: p^x = q, q^y = r, r^z = p.

  • Substitute stepwise: from p^x = q and q^y = r we get p^{xy} = r. Using r^z = p then gives p^{xyz} = p.

  • Since p β‰  0, equate exponents to conclude xyz = 1.

Therefore the value of the product xyz is 1.

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