Tìm x, biết: 8x^3 - 12x^2 + 6x - 1 = 0
Tìm x, biết: 8x3 – 12x2 + 6x – 1 = 0.
8x3 – 12x2 + 6x – 1 = 0
\( \Leftrightarrow \) (8x3 – 1) – (12x2 – 6x) = 0
\( \Leftrightarrow \) [(2x)3 – 1] – 6x(2x – 1) = 0
\( \Leftrightarrow \) (2x – 1)(4x2 + 2x + 1) – 6x(2x – 1) = 0
\( \Leftrightarrow \) (2x – 1)(4x2 + 2x + 1 – 6x) = 0
\( \Leftrightarrow \) (2x – 1)(4x2 – 4x + 1) = 0
\( \Leftrightarrow \)(2x – 1)(2x – 1)2 = 0
\( \Leftrightarrow \) 2x – 1 = 0
\( \Leftrightarrow x = \frac{1}{2}\).
Vậy phương trình đã cho có nghiệm là: \(x = \frac{1}{2}\).