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A quadratic equation has two roots, one root, or no real root.

This chapter tells you which, before you solve anything.

A real root is one you can mark on the number line.

This is Chapter 4, Quadratic Equations, in your NCERT Maths book.

What you will learn

• Straighten it first — tidy first, then read a, b and c.
• What a root is — a value that balances the equation.
• Split and solve — split the middle term, then use brackets.
• One formula — roots for every equation that has real roots.
• The decider — b² − 4ac counts the roots before you solve.
• Two roots, two kinds — rational roots or irrational roots.
• Twice the same, or never — one repeated root, or no real root.
• Choosing the method, checking the answer — split or formula, then check.
• Stories that square — a word problem becomes an equation.

Need a quick recap?

These earlier lessons help most.

• The degree names it — the highest power of the letter.
• The pair with two jobs — splitting a middle term.
• A zero is an input — one substitution tests it.
• Factors hand over their zeros — a zero factor gives a zero product.
• Every number so far — rational numbers, one whole over another.
• A length with no fraction — irrational numbers are real too.