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2013年6月27日SAT官方每日一题---数学选择

　　下面是2013年6月27日的SAT官方每日一题的内容，是关于数学方面的，题型是选择。SAT官方每日一题是collegeboard每天都会发布的题目，关于SAT考试的三个部分的各个题型。大家和无忧小编一起来看一下这个SAT官方每日一题吧。

　　SAT官方每日一题之数学---选择：

　　Mathematics > Standard Multiple Choice

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

　　

y = (x^2) minus (4 times x) + c)

 

　　In the quadratic equation above,cis a constant. The graph of the equation in thex y planecontains the points(minus 2 comma 0)and(6 comma 0). What is the value ofc?

　　(A)negative 12

　　(B)negative 6

　　(C)4

　　(D)6

　　(E)12

　　The correct answer is A

　　Explanation

　　Since the graph ofy = (x^2) minus (4 times x) + cin thexy-planecontains the point(negative 2 comma 0), it follows that substituting the valuex = negative 2intoy = (x^2) minus (4 times x) + c)yieldsy = 0. Hence0 = ((negative 2)^2) minus 4 times (negative 2) + c, which simplifies to0 = 4 minus (negative 8) + c, or0 = 12 + c. Therefore,c = negative 12.

　　Alternatively, since the graph ofy = (x^2) minus (4 times x) + c)in thexy-planecontains the points(negative 2 comma 0)and(6 comma 0), and the coefficient ofx^2is1, the equation is equivalent toy = (x +2) times (x minus 6), which multiplies out toy = (x^2) minus (4 times x) minus 12. Therefore,c = negative12.

　　下面为大家提供一些和这些SAT官方每日一题相似的题目，供大家练习：

　　If the graph of the functionfis a line with slope2, which of the following could be the equation off?

　　(A)function f of x = (4 times x) minus 2 

　　(B)function f of x = (2 times x) + 4 

　　(C)function f of x = negative (2 times x) minus 2 

　　(D)function f of x = ((1 over 2) times x) + 2 

　　(E)function f of x = negative ((1 over 2) times x) + (1 over 2) 

　　The correct answer is B

　　Explanation

　　The graphs of all the given functions are lines, and the equations are all in the formy = (m times x) + b. When a linear equation is in the formy = (m times x) + b, the slope of the graph of the equation ism, the coefficient ofx. The graph of the functionfis a line with slope2, so the only choice that could be the equation offisfunction f of x = (2 times x) + 4.

　　以上就是关于2013年6月27日SAT官方每日一题中数学部分的详细内容，包括了题目和选项以及答案，后面附有一道相关的练习题。大家可以在备考SAT的过程中关注SAT每日一题的内容，这样就可以更好有不间断的练习，也就能在日积月累的过程中得到提高。

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