1) -3x + 15 - 2x - 2 = 23
5x = -10
x = -2
2)
2x - 5 = 0 или x + 3 = 0
2x = 5 x = -3
x = 2,5
Ответ: -3 и 2,5
3) 2x² + 7x + 6 = 0
D = 49 - 48 = 1
x1 = (-7-1)/4 = -2
x2 = (-7+1)/4 = -1,5
Ответ: -2 и -1,5
4) x ≠-2
5x + 8 = 6x + 12
x = -4
Ответ: -4
5) x³ - 6x²-4x +24 = 0
x²(x-2) - 4x(x-2) - 12(x-2) = 0
(x-2)(x² - 4x-12) = 0
(x-2)(x-6)(x+2) = 0
x1 = -2
x2 = 2
x3 = 6
Ответ: -2; 2; 6