下面是出国留学网GMAT频道整理的2015年6月GMAT数学机经(三)，欢迎阅读。
11 If the function f(x) = x^2 + px + 9 has the solution x1 and x2, what is the value of p^2?
(1) x1 = x2
(2) x1 + x2 = -6
12 What is the remainder when 15n is divided by 6?
(1) n is an even integer.
(2) n is divisible by 3.
13 Which of the following cannot be the number of diagonals of a polygon?
A. 5
B. 6
C. 9
D. 14
E. 20
14 In a set of ten integers, if first five integers are added x, respectively, and if the rest integers are added y, respectively, what is the difference of the average of before and after addition?
(1) x + y = 5.
(2) x – y = 7.
15 The function f(x) = x^2 + 1. If hw is not 0, is f(w – h)/h > f(w + h)/h?
(1) 0 < h <1
(2) w < 0
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