Èrcì fāngchéng de pànbiéshì dàyú líng, shuōmíng yǒu liǎng gè bùtóng de shíshù gēn.
When the quadratic equation's discriminant is greater than zero, it has two distinct real roots.
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判 (judge) + 别 (distinguish) + 式 (formula) - literally 'judging-distinguishing formula.' For ax² + bx + c = 0, that is Δ = b² − 4ac, the value that judges whether the roots are real, repeated, or complex.