1)(x + 1)(x + 2) 2)(x - 3)(x + 4) 3)(2x + 1)(x - 5) 4)(3x - 2)(x + 6) 5)(x² + 2x)(x + 1) 6)(a + 2)(a - 2) 7)(x - 1)(x² + x + 1) 8)(2a + 3)(a² - a + 4) 9)(x² + 1)(x² - 3x) 10)(a - b)(a + 3b)

Вариант 1

1. \( (x + 1)(x + 2) = x^2 + 2x + x + 2 = x^2 + 3x + 2 \)

2. \( (x - 3)(x + 4) = x^2 + 4x - 3x - 12 = x^2 + x - 12 \)

3. \( (2x + 1)(x - 5) = 2x^2 - 10x + x - 5 = 2x^2 - 9x - 5 \)

4. \( (3x - 2)(x + 6) = 3x^2 + 18x - 2x - 12 = 3x^2 + 16x - 12 \)

5. \( (x^2 + 2x)(x + 1) = x^3 + x^2 + 2x^2 + 2x = x^3 + 3x^2 + 2x \)

6. \( (a + 2)(a - 2) = a^2 - 4 \)

7. \( (x - 1)(x^2 + x + 1) = x^3 + x^2 + x - x^2 - x - 1 = x^3 - 1 \)

8. \( (2a + 3)(a^2 - a + 4) = 2a^3 - 2a^2 + 8a + 3a^2 - 3a + 12 = 2a^3 + a^2 + 5a + 12 \)

9. \( (x^2 + 1)(x^2 - 3x) = x^4 - 3x^3 + x^2 - 3x \)

10. \( (a - b)(a + 3b) = a^2 + 3ab - ab - 3b^2 = a^2 + 2ab - 3b^2 \)