@ @¶ìÿa@óÝy‹¾a@ u@ @XX . () . x 2 + 6x − 2 = 0 () : () x 2 + 6x = 2 x 3 x 2 + 6x + 9 = 2 + 9 () (x + 3)2 = 11 () x + 3 = ± 11 x = −3 ± 11 .x2 = −3 − 11 x1 = −3 + 11 . x 2 + 6x + 11 = 0 ( ) x2 + 6x = −11 x 2 + 6x + 9 = −11 + 9 (x + 3)2 = −2