Equations

An inequality compares two expressions using <, >, ≤ or ≥. Solving an inequality is like solving an equation, except that multiplying or dividing by a negative number reverses the inequality sign.

A linear equation is an algebraic equation where each term is either a constant or a single variable raised to the first power.

Substitution means replacing a letter (variable) in an expression with a given number and then calculating the result. It is used to evaluate formulae and check solutions to equations.

A system of equations is a set of two or more equations with the same variables, solved simultaneously.

A two-step equation needs exactly two operations to isolate the variable. Undo addition or subtraction first, then undo multiplication or division.

How to translate word problems into algebraic equations and solve them step by step.