Olympiad Maths Prep

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Problem 466

AMC 12 late, AIME early
Algebra Difficulty 4.9 Find the answer

5. Solve the inequality 12x+52+x<1\frac{1}{2-x}+\frac{5}{2+x}<1.

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Official solution

# Solution:

12x+52+x<1,2+x+5(2x)1(2x)(2+x)(2x)(2+x)<0\frac{1}{2-x}+\frac{5}{2+x}<1, \frac{2+x+5(2-x)-1(2-x)(2+x)}{(2-x)(2+x)}<0,

!

2+x+105x+x24(2x)(2+x)<0,x24x+8(2x)(2+x)<0\frac{2+x+10-5x+x^2-4}{(2-x)(2+x)}<0, \frac{x^2-4x+8}{(2-x)(2+x)}<0

Answer: (,2)(2,+)(-\infty, -2) \cup (2, +\infty).

Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic, difficulty and ordering added by this site.