Maths Olympiad Prep

Track / Stage 4 / 138 of 340 #398 of 1964

Problem 398

AMC 12 late, AIME early
Algebra Difficulty 4.8 Find the answer

5. Solve the inequality x+23x+1x22x1\frac{x+2}{3 x+1} \leq \frac{x-2}{2 x-1}.

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Official solution

Solution: x+23x+1x22x1;x+23x+1x22x10,(x+2)(2x1)(x2)(3x1)(3x+1)(2x1)0\frac{x+2}{3 x+1} \leq \frac{x-2}{2 x-1} ; \frac{x+2}{3 x+1}-\frac{x-2}{2 x-1} \leq 0, \frac{(x+2)(2 x-1)-(x-2)(3 x-1)}{(3 x+1)(2 x-1)} \leq 0, 2x2+3x23x2+5x+2(3x+1)(2x1)0,8x2+8x(3x+1)(2x1)0,x(x8)(3x+1)(2x1)0\frac{2 x^{2}+3 x-2-3 x^{2}+5 x+2}{(3 x+1)(2 x-1)} \leq 0, \frac{-8 x^{2}+8 x}{(3 x+1)(2 x-1)} \leq 0, \frac{-x(x-8)}{(3 x+1)(2 x-1)} \leq 0

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