Solving Equations and Inequalities

General Mathematics — Second Secondary

Common mistakes

Key points

Forgetting the negative casethe equation |x| = 5 has two solutions, not one.

Confusing “or” with “and”the solution of |x| > 2 is x > 2 or x < −2, not x > 2 and x < −2.

Reversing the inequality incorrectlymultiplying or dividing an inequality by a negative number reverses its sign.

Writing a union as a single intervalwhen the solution consists of two separate intervals, write the union of the two.

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