3 х^2-18 х + (6-х) = 0 х^2-9 х - (х-9) = 0 4 х-х^2 - (2 х-8) = 0

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28 февраля, 18:48

3 х^2-18 х + (6-х) = 0 х^2-9 х - (х-9) = 0 4 х-х^2 - (2 х-8) = 0

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Тигран Миронов · Answer 1

1) 3 х^2 - 18 х + (6 - х) = 0;

3 х^2 - 18 х + 6 - х = 0;

3 х^2 - 19 х + 6 = 0.

D = b^2 - 4ac = 361 - 4 * 3 * 6 = 289.

x1 = (-b + √D) / 2a = (19 + 17) / 6 = 36/6 = 6.

x2 = (-b - √D) / 2a = (19 - 17) / 6 = 2/6 = 1/3.

2) x^2 - 9x - (x - 9) = 0;

x^2 - 9x - x + 9 = 0;

x^2 - 10x + 9 = 0.

D = 100 - 4 * 1 * 9 = 64.

x1 = (10 + 8) / 2 = 18/2 = 9.

x2 = (10 - 8) / 2 = 2/2 = 1.

3) 4x - x^2 - (2x - 8) = 0;

4x - x^2 - 2x + 8 = 0;

-x^2 + 2x + 8 = 0;

x^2 - 2x - 8 = 0.

D = 4 + 4 * 1 * 8 = 4 + 32 = 36.

x1 = (2 + 6) / 2 = 8/2 = 4.

x2 = (2 - 6) / 2 = - 4/2 = - 2.