А2. (2x + 1)(x^2 + 2x - 3) = 0
2x + 1 = 0
2x = -1
x = -1/2
или
x^2 + 2x - 3 = 0
D = b^2 - 4ac = 4 - 4*(-3) = 4 + 12 = 16
x1 = (-2 + 4)/2 = 2/2 = 1
x2 = (-2 - 4)/2 = -6/2 = -3
-12*1*(-3) = 3/2 = 1.5
Ответ: 2)
A5. (2 - 3x)*(x^2 - 5x+ 13) = 0
2 - 3x = 0
3x = 2
x = 2/3
или
x^2 - 5x + 13 = 0
D = b^2 - 4ac = 15 - 4*13 < 0 => нет корней.
Ответ: 1)