一色屋精品亚洲香蕉网站_亚洲欧美一区二区三区久久_国产毛片精品国产一区二区三区_在线国产精品播放_欧美激情综合亚洲一二区_国产精品久久久久久久7电影_亚洲美女一区_免费成人黄色av_国内精品久久久久影院色_亚洲大胆视频_久久久精品欧美丰满_国产在线精品成人一区二区三区_樱桃视频在线观看一区_久久蜜桃av一区精品变态类天堂_国产午夜精品一区二区三区欧美_欧美精品自拍偷拍动漫精品

　　環球教育SAT考試頻道：今天為大家帶來2016年4月20日SAT考試官方每日一題數學部分附答案和解析，希望可以幫助到考生們。

　　每日一題：

　　Mathematics>Standard Multiple Choice

　　Read the following SAT test question and then click on a button to select your answer.

　　-(a-1)(b-1)(c-1)

　　Which of the following is equivalent to the expression above?

　　A. (1-a)(b-1)(1-c)

　　B. -(1-c)(1-b)(1-a)

　　C. (c-1)(1-b)(a-1)

　　D. -(a-1)(1-b)(c-1)

　　答案：C

　　解析：

　　Choice C is correct. Subtraction is not commutative. (p-1) is not the same as (1-p).

　　However, it is true that (1-p)=-(p-1): p-1=space-(-p+1) space=space-(1-p)

　　We can conclude that when the order of two factors being subtracted in an expression is changed, it is the same as multiplying the original expression by-1.

　　Start with the original expression -1*(a-1)(b-1)(c-1) and change the order of the subtraction for one set of parentheses: -1*-1*(a-1)(1-b)(c-1)=(a-1)(1-b)(c-1)

　　Multiplication is commutative, so we can reorder the parenthesized groups to get (c-1)(1-b)(a-1).

　　閱讀更多：關注環球教育SAT考試頻道