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题目： If x + y = 7 and x – y = 3, then $$x^{2} - y^{2} =$$

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题目： $${1}\over{{3}+\frac{4}{7}}$$=

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题目： If $$4^{x} + 4^{-x} = 2$$, which of the following is the value of x?

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题目： In the right triangle pictured to the right, what is the value of x?

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题目： A certain square has sides of length x. If the length of each side is doubled, then which of the following represents the area of the resulting square, in terms of x?

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题目： Which of the following has a value greater than 1?

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题目： In the rectangular coordinate plane points X and Z lie on the same line through the origin and points W and Y lie on the same line through the origin. If$$ a^{2} + b^{2} = c^{2} + d^{2} and e^{2} + f^{2} = g^{2} + h^{2}$$, what is the value of length XZ – length WY?

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题目： Ben is driving on the highway at x miles per hour. (One mile equals 5,280 feet.) Ben's tires have a circumference of y feet. Which of the following expressions gives the number of revolutions each wheel turns in one hour?

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题目： How many units long is the straight line segment that connects the points (-1,1) and (2,6) on a rectangular coordinate plane?

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题目： If the side length of Square B is twice that of Square A, the area of Square B is how many times the area of Square A?

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题目： Given the circle to the right, with center O, diameter AOB, a radius of 5, and the inscribed triangle ABC, what is the length of AC?

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题目：

To decrease the number of crimes in city Y, the city's Police Commissioner proposed taking some police officers from low-crime districts of the city and moving them to high-crime districts of the city. His proposal is based on city Y crime data that show that the number of crimes in any district of the city decreases when additional police officers are moved into that district.

The Police Commissioner's proposal depends on which of the following assumptions?

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题目：

Most water companies in the United States add fluoride to tap water to help prevent cavities. Some dentists argue, however, that this practice actually causes more harm than good because people overestimate the protection afforded by the fluoride and do not take the proper steps to care for their teeth, such as brushing and flossing after every meal. If water companies did not add fluoride, the dentists claim, people would be forced to be more active in their dental hygiene and tooth decay would decline as a result.

Which of the following, if true, most weakens the dentists' claims?

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题目：

Footwear designer John de los Santos last year released several limited editions of his best-known model of sneaker in exotic colors and prints. Although the new releases were priced substantially higher than their counterparts in more traditional colors, they sold out within a week of their release, and have since been selling on the resale market for up to four times the original price. The cost of producing the sneakers in exotic prints is no greater than that of producing them in more traditional colors, so de los Santos could earn a higher profit per unit by producing a greater percentage of his sneakers in such prints.

Which of the following is an assumption made in drawing the conclusion above?

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题目：

Weight loss programs that guarantee results mislead their customers. No program can ensure that someone who follows it will lose weight. These programs prey upon unhappy and insecure people who are often driven more by emotion than by reason. Moreover, many people who lose weight while on a program eventually regain the weight within a year. So while the programs' claims may be true for a short period, customers will be disappointed in the long run.

The two portions in boldface play which of the following roles?