`6x^4-5x^3-38x^2-5x+6=0`
`=>6x^4-18x^3+13x^3-39x^2+x^2-3x-2x+6=0`
`=>6x^3(x-3)+13x^2(x-3)+x(x-3)-2(x-3)=0`
`=>(6x^3+13x^2+x-2)(x-3)=0`
`=>[6x^3+12x^2+x^2+2x-x-2](x-3)=0`
`=>[6x^2(x+2)+x(x+2)-(x+2)](x-3)=0`
`=>(6x^2+x-1)(x+2)(x-3)=0`
`=>(6x^2-2x+3x-1)(x+2)(x-3)=0`
`=>[6x(x-1/3)+3(x-1/3)](x+2)(x-3)=0`
`=>(6x+3)(x-1/3)(x+2)(x-3)=0`
`=>`\(\left[ \begin{array}{l}6x+3=0\\x-\frac{1}{3}=0\\x+2=0\\x-3=0\end{array} \right.\)`=>` \(\left[ \begin{array}{l}x=\frac{-1}{2}(tm)\\x=\frac{1}{3}(tm)\\x=-2(tm)\\x=3(tm)\end{array} \right.\)
vậy `x `có nghiệm `S{-1/2;1/3;-2;3}`
