Equations, Inequalities & Quadratics

What you'll learn

Quadratic graphs, solving linear inequalities, solving simultaneous linear equations, and solving quadratics by factorisation.

• A quadratic graph is a U-shaped (or n-shaped) curve
• The roots of a quadratic are where its graph crosses the x-axis
• Solving a linear inequality is almost like solving an equation, with one key rule
• Simultaneous equations by substitution: make one letter the subject, then swap it in
• Simultaneous equations by elimination: add or subtract the equations to remove a letter
• Simultaneous equations by graph: the solution is where the two lines meet
• Solving a quadratic equation by factorisation uses the zero product rule