1) (x + 7)(3x + 4) = (2x - 1)( x - 1)
3x² + 4x + 21x + 28 = 2x² - 2x - x + 1
3x² - 2x² + 25x + 3x + 28 - 1 =0
x² + 28x + 27 = 0
D = b² - 4ac = 784 - 4 × 27 = 784 - 108 = 676 = 26²
x1 = ( - 28 + 26) / 2 = - 1
x2 = ( - 28 - 26) / 2 = - 27
Ответ: x1 = - 1, x2 = - 27.
2) ( 2x + 3)( x + 3) = (2x - 1)( x - 5)
2x² + 6x + 3x + 9 = 2x² - 10x - x + 5
2x² - 2x² + 9x + 11x + 9 - 5 = 0
20x + 4 = 0
20x = - 4
x = - 4/20
x = - 0,2
Ответ: x = - 0,2.