BYou are given that x2y > 0, which means that the product of the two numbers x2 and y is positive. Recall that the product of tw

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答案B

解析 You are given that x2y > 0, which means that the product of the two numbers x2 and y is positive. Recall that the product of two numbers is positive only if both numbers are positive or both numbers are negative. The square of a number is always greater than or equal to 0. In this case, x2 cannot equal 0 because the product x2y is not 0. Thus, x2 is positive and it follows that y is also positive.
    You are also given that xy2 < 0, which means that the product of the two numbers x and y2 is negative. The product of two numbers is negative only if one of the numbers is negative and the other number is positive. In this case, y2 cannot be negative because it is the square of a number, and it cannot be 0 because the product x2y is not 0. Thus, y2 is positive and so x must be negative.
    Because x is negative and y is positive, y must be greater than x, and the correct answer is Choice B.
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