@ @¶ìÿa@óÝy‹¾a@ u@ @YR [The Discriminant of The Quadratic] (.) .∆ b2 − 4ac ∆ = b2 − 4ac x = −b ± ∆ 2a : () ∆=0 . x1 = x2 = −b 2a ∆>0 () .x2 = −b − ∆ x1 = −b + ∆ 2a 2a . ∆ ∆<0 () () . ∆ cba . m () :x 2 − 2x + m = 0 () () () .