Quadratic Equations

advanced28 min read

Solving quadratics by factorisation and by formula, reading the discriminant, using the sum and product of roots, forming a quadratic from its roots, and the compare-the-roots question.

What you will be able to do

Solve a quadratic by factorisation and by the quadratic formula.
Use the discriminant to state the nature of the roots without solving.
Apply sum of roots = -b/a and product of roots = c/a, and form a quadratic from given roots.
Answer a compare-the-roots question by finding both root sets and checking the ranges.

What is inside this lesson

1Standard form
2The quadratic formula
3Solving by factorisation
4The discriminant and the nature of the roots
5Sum and product of the roots
6The compare-the-roots question
7Worked examples
8Common mistakes
9Quick revision
10Practice

The lesson itself is for members

Reading the 10 sections above, the worked examples and the practice set is free — the whole knowledge base is on the free plan, along with flashcards, private notes and Ask Onely.

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