Choose the method

Steps

1. Move everything to one side: ax² + bx + c = 0.
2. Try to factorise (fastest). Then set each factor to 0.
3. If it won't factorise, use the formula: x = [−b ± √(b² − 4ac)] / 2a.
4. Check one root by substituting.

Why factorising works: if A × B = 0, then A = 0 or B = 0. This only works with 0 on the right.

Want to check an answer? Quadratic equation calculator shows every step.

For the whole topic, read Quadratic equations in one unknown: key points, common mistakes and how the DSE tests it.

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