Bunuel wrote:
If \(xy > 0\) and \(yz < 0\), then which of the following must be negative?
A \(xyz\)
B \(xy^2z\)
C \(x^2y^2z\)
D \(x^2y^2z^2\)
E \(\frac{xy}{z}\)
IMO B
If \(xy > 0\) and \(yz < 0\)
there can be 2 cases
x can be +ive, y can be +ive
& y can be +ive, z can be -ive
x can be -ive, y can be -ive
& y can be -ive, z can be +ive
Now just go through the options one by one
A \(xyz\), -ive or +ive, depending on the mentioned cases
B \(xy^2z\), always -ive
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If you notice any discrepancy in my reasoning, please let me know. Lets improve together.
Quote which i can relate to.
Many of life's failures happen with people who do not realize how close they were to success when they gave up.