, ax2 + bx + = 0, , b, - - , . . . , :

D = b2 - 4ac . . D > 0, . . , D < 0, , D = 0, . : x1 +2= -b/a, x1x2= /, . . . . ( - 1)( - x2). = ax2 + bx + , (-b/2a; - b2/4a) , ; a. . . .

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