Объяснение:
x^2 - 2x - 8 = 0;
D = b^2 - 4ac;
D = (-2)^2 - 4 * 1 * (- 8) = 4 + 32 = 36; √Db = 6;
x = (- b ± √D)/(2a);
x1 = (- (- 2) + 6)/(2 * 1) = (2 + 6)/2 = 8/2 = 4;
x2 = (- (- 2) - 6)/(2 * 1) = (2 - 6)/2 = - 4/2 = - 2.
ответ. - 2; 4.
