đặt x+3=a
pt trở thành: (a-1)2+a3+(a+1)4=2
\(\leftrightarrow a^2-2a+1+a^3+a^4+4a^3+6a^2+4a+1=2\)
\(\leftrightarrow a^4+5a^3+7a^2+2a=0\)
\(\leftrightarrow a\left(a^3+2a^2+3a^2+6a+a+2\right)=0\)
\(\leftrightarrow a\left(a+2\right)\left(a^2+3a+1\right)=0\)
\(\leftrightarrow\left[\begin{matrix}a=0\\a=-2\\a^2+3a+1=0\end{matrix}\right.\leftrightarrow\left[\begin{matrix}a=0\\a=-2\\a=\frac{\sqrt{5}-3}{2}\\a=\frac{-\sqrt{5}-3}{2}\end{matrix}\right.\)
\(\leftrightarrow\left[\begin{matrix}x=-3\\x=-5\\x=\frac{\sqrt{5}-3}{2}-3=\frac{\sqrt{5}-9}{2}\\x=\frac{-\sqrt{5}-3}{2}-3=\frac{-\sqrt{5}-9}{2}\end{matrix}\right.\)
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