1) 5x + (2x+1) (x-3) = -2 2) (2x+3) (3x+1) = 11x+30

Question

Герман Семенов

Математика

29 апреля, 14:51

1) 5x + (2x+1) (x-3) = -2 2) (2x+3) (3x+1) = 11x+30

+3

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Vanilinka · Answer 1

1) 5 * x + (2 * x + 1) * (x - 3) = - 2;

Раскроем скобки.

5 * x + 2 * x^2 - 2 * 3 * x + x - 3 = - 2;

2 * x^2 + 5 * x - 6 * x + x - 3 = - 2;

2 * x^2 + 5 * x - 5 * x - 3 = - 2;

2 * x^2 - 3 = - 2;

2 * x^2 - 3 + 2 = 0;

2 * x^2 - 1 = 0;

2 * (x^2 - 1/2) = 0;

x^2 - 1/2 = 0;

(x - √2/2) * (x + √2/2) = 0;

{ x - √2/2 = 0;

x + √2/2 = 0;

{ x = √2/2;

x = - √2/2.

2) (2 * x + 3) * (3 * x + 1) = 11 * x + 30;

6 * x^2 + 2 * x + 9 * x + 3 = 11 * x + 30;

6 * x^2 + 11 * x + 3 = 11 * x + 30;

6 * x^2 + 3 = 30;

6 * x^2 + 3 - 30 = 0;

6 * x^2 - 27 = 0;

3 * (2 * x^2 - 9) = 0;

2 * x^2 - 9 = 0;

{ √2 * x - 3 = 0;

√2 * x + 3 = 0;

{ x = 3/√2;

x = - 3/√2.