\(8x^3+12x^2+6x+1=0\) \(\Leftrightarrow\left(2x\right)^3+3.\left(2x\right)^2.1+3.2x.1^2+1^3\) \(\Leftrightarrow\left(2x+1\right)^3=0\) \(\Leftrightarrow2x+1=0\) \(\Leftrightarrow2x=-1\Leftrightarrow x=-\dfrac{1}{2}\)Câu trả lời: \(8x^3+12x^2+6x+1=0\) \(\Leftrightarrow\left(2x\right)^3+3.\left(2x\right)^2.1+3.2x.1^2+1^3\) \(\Leftrightarrow\left(2x+1\right)^3=0\) \(\Leftrightarrow2x+1=0\) \(\Leftrightarrow2x=-1\Leftrightarrow x=-\dfrac{1}{2}\)