Re: If x < y < –1, then which one of the following expressions i
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30 Mar 2019, 11:25
Both x and y are negative. A negative squared is positive, so x² and y² are both positive. A positive times a positive is positive, so x²y² is definitely positive. Choice D is correct.
Since x² is positive, –(x²), which is what choice A means, is negative.
Y is negative, so choice B is negative.
In choice C, x² is positive, but y is negative, and a positive times a negative is negative. So x²y is negative.
And finally, for choice E, y is negative, and x² is positive. When we subtract a positive, though, the number gets smaller. So we're making y smaller and it was already negative to begin with.