@ @XU@ @pý†bɾa@ @ [Quadratic Equation] (.) ax2 + bx + c = 0 cba .a ≠ 0 . [By Factorization] (.) : () .ab = 0 ⇒ a = 0 b = 0 . . 3x 2 + 5x = 0 3x 2 + 5x = 0 x(3x + 5) = 0 x =0 3x + 5 = 0 x =0 x = −5 3 x1 = 0 ( ) .x2 = −5 3