2. Determine the discriminant and calculate δ (Greek letter, transliteration for Delta).

3. If δ > 0, the equation has two unequal real roots in the real number field:

If δ = 0, the equation has two equal real roots in the real number field:

If δ

It should be pointed out that:

There must be no case where a quadratic equation with one variable cannot be solved by formula method.

However, if you can directly find the root or factorization, you'd better use the direct open method and factorization method.