\(=>x^3+6x^2+12x+8-x^3+27+6x^2+12x+6=15\)
\(=>12x^2+24x+41-15=0\)
\(=>12x^2+24x+26=0\)
\(=>12\left(x^2+2x+1\right)+14=0\)
\(=>12\left(x+1\right)^2+14=0\)
\(=>2[6\left(x+1\right)^2+7]=0\)
\(=>6\left(x+1\right)^2+7=0\)
Mà \(\left(x+1\right)^2\ge0\)nên \(6\left(x+1\right)^2+7>0\)
Vậy ko có giá trị x nào thỏa mãn đề bài