1) 3x(4 + 12x) - (6x - 1)(6x + 1) = 11x
12x + 36x² - (36x² - 1) = 11x
12x + 36x² - 36x² + 1 - 11x = 0
x + 1 = 0
x = - 1
2) (2x - 1)(2x + 1) = 2(x - 3)² + x(2x - 3)
4x² - 1 = 2(x² - 6x + 9) + 2x² - 3x
4x² - 1 = 2x² - 12x + 18 + 2x² - 3x
4x² - 1 = 4x² - 15x + 18
4x² - 4x² + 15x = 18 + 1
15x = 19
3) (4x - 3)² - 4(x - 2)(x + 2) - (3x - 4)(4x + 3) = - 4
16x² - 24x + 9 - 4(x² - 4) - 12x² - 9x + 16x + 12 = - 4
4x² - 17x + 21 - 4x² + 16 = - 4
- 17x + 37 = - 4
- 17x = - 41
4) (2 - 3x)(4 + 6x + 9x²) + 3x(3x - 1)(3x + 1) = x
8 + 12x + 18x² - 12x - 18x² - 27x³ + 3x(9x² - 1) - x = 0
8 - x - 27x³ + 27x³ - 3x = 0
- 4x = - 8
x = 2