Students' strategies and difficulties: the case of algebraic inequalities

This article describes a study related to secondary school students' ways of thinking about linear, quadratic, rational and square-root inequalities. Findings show that using graphic representations of parabolas when solving rational and quadratic inequalities usually yielded correct solutions. Difficulties arose when students failed to reject the excluded values or chose inappropriate, logical connectives. The most prevalent source of difficulties was inappropriate analogies between equations and inequalities. The article concludes with some suggested educational implications.