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新SAT数学练习题目
Read the following SAT test question and thenclick on a button to select your answer.
Which of the following equations represents a line inthe x y-plane with x-intercept at (-15,0) and y-intercept at (0,-9)?
A.x/15+y/9=1
B.-x/15-y/9=1
C.x/9-y/15=1
D.-x/9+y/15=1
重点单词讲解：
equation [i'kweiʃən] n. 相等，方程(式), 等式，均衡
multiple ['mʌltipl] adj. 许多，多种多样的
slope [sləup] n. 倾斜，斜坡，斜面，斜线，斜率
答案：B
解析：
Choice B is correct. Using the points given, first findthe slope of the line:
-9-0/0-(-15) =-3/5. The y-intercept of the line is –9,so the equation of the line can be written as y=(-3/5)x-9.
Since none of the answer choices are in this form, the equation must be rewritten. First, add(3/5)x to both sides of the equation, resulting in (3/5)x+y=-9. Next, divide both sides of theequation by –9, which yields (3/5)/-9x+y/(-9)=9/-9 which can be simplified to -x/15-y/9=1.
新SAT数学练习题目
Read the following SAT test question and thenclick on a button to select your answer.
For each of the largest 21 airline companies inEurope, the average flight delay was calculatedand is shown in the dot plot above. If the dots representing the two airlines with the longestaverage flight delays are removed from the dot plot, what will happen to the mean, median,and range of the new data set?
A.Only the mean will decrease.
B.Only the mean and range will decrease.
C.Only the mean and median will decrease.
D.The mean, median, and range will decrease.
重点单词讲解：
multiple ['mʌltipl] adj. 许多，多种多样的
range [reindʒ] n. 范围，行列，射程，山脉，一系列
flight [flait] n. 飞行，航班
plot [plɔt] n. 阴谋，情节，图，(小块)土地，
delay [di'lei] v. 耽搁，推迟，延误
calculated ['kælkjuleitid] adj. 计算出的;适合的;有计划的 v. 计算;估计;
答案：B
解析：
Choice B is correct.