12. If \[2x < y < 0\], which of the following is greatest?
(A) \[-2x\]
(B) \[-(2x + y)\]
(C) \[2x\]
(D) \[0\]
(E) \[-y\]

13. Carlos delivered \[n\] packages on Monday, 4 times as many packages on Tuesday as on Monday, and 3 more packages on Wednesday than on Monday. What is the average (arithmetic mean) number of packages he delivered per day over the three days?
(A) \[2n - 3\]
(B) \[2n - 1\]
(C) \[2n + 1\]
(D) \[2n + 3\]
(E) \[6n + 1\]

14. If \[(a + b)^{\frac{1}{2}} = (a - b)^{-\frac{1}{2}}\], which of the following must be true?
(A) \[b = 0\]
(B) \[a + b = 1\]
(C) \[a - b = 1\]
(D) \[a^2 + b^2 = 1\]
(E) \[a^2 - b^2 = 1\]

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