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Equations & Inequalities

Solve linear equations and inequalities

Solving Linear Equations

An equation has an equals sign (=). To solve, isolate the variable by performing the same operation on both sides. What you do to one side, you must do to the other.
Example

Solving Equations Step by Step

3x + 7 = 22 3x = 22 − 7 3x = 15 x = 5 2(x − 3) = 10 2x − 6 = 10 2x = 16 x = 8

Inequalities

An inequality uses <, >, ≤ or ≥ instead of =. Solve the same way as equations, BUT if you multiply or divide by a negative number, flip the inequality sign.
Example

Solving Inequalities

2x + 3 < 11 2x < 8 x < 4 −3x ≥ 12 x ≤ −4 (flip sign because we divided by −3)
Note

Remember

Equations: balanced scales — keep both sides equal. Inequalities: remember to flip the sign when multiplying or dividing by a negative. Represent solutions on a number line.

Key Vocabulary

EquationA mathematical statement that two expressions are equal
InequalityA statement that one expression is greater or less than another
SolutionThe value that makes the equation true
IsolateGet the variable alone on one side

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