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Working with linear equations and inequationsInequations

As with other equations and inequations, when working with algebraic equations and inequations it is key to change operation when you change side.

Part of MathsAlgebraic skills

Inequations

When solving inequations, the inequality sign can mostly be treated the same way as an equals sign.

Example one

Solve the inequation \(3x + 2 \le - 4\)

Answer

\(3x + 2 \le - 4\)

\(3x \le - 4 - 2\)

\(3x \le - 6\)

\(x \le \frac{{ - 6}}{3}\)

\(x \le - 2\)

Example two

Solve the inequation \(2x-1\,\textgreater 9\)

Answer

\(2x\,\textgreater 9+1\)

\(2x\,\textgreater 10\)

\(x\,\textgreater \frac{10}{2}\)

\(x\,\textgreater 5\)

As stated previously, the same rules for equations can be applied to inequations apart from one exception:

When multiplying (or dividing) an inequation by a negative number, switch the inequality symbol round.

For example, greater than (>) becomes less than (<).

Now try the example question below.

Question

Solve the inequation \(5(w - 1) - 8w \ge - 11\)