【冲刺10月SAT考试】SAT数学备考练习题（12）

2017年07月13日14:44 来源：互联网

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本文分享给大家冲刺10月SAT数学练习题的最后一部分，本文共计2道题，供大家练手用，希望大家有收获。

1. If f(x) = x2 – 3, where x is an integer, which of the following could be a value of f(x)?

I 6

II 0

III -6

A. I only

B. I and II only

C. II and III only

D. I and III only

E. I, II and III

Correct Answer: A

解析:

Choice I is correct because f(x) = 6 when x=3. Choice II is incorrect because to make f(x) = 0, x2 would have to be 3. But 3 is not the square of an integer. Choice III is incorrect because to make f(x) = 0, x2 would have to be –3 but squares cannot be negative. (The minimum value for x2 is zero; hence, the minimum value for f(x) = -3)

2. For how many integer values of n will the value of the expression 4n + 7 be an integer greater than 1 and less than 200?

A. 48

B. 49

C. 50

D. 51

E. 52

Correct Answer: C

解析:

1 < 4n + 7 < 200. n can be 0, or -1. n cannot be -2 or any other negative integer or the expression 4n + 7 will be less than1. The largest value for n will be an integer < (200 - 7) /4. 193/4 = 48.25, hence 48. The number of integers between -1 and 48 inclusive is 50