Ta có :
\(\left(x+2\right)\left(x^2-2+2\right)=0\)
\(\left(x+2\right).\left[\left(x^2-2.\frac{1}{2}x+\frac{1}{4}\right)+\frac{7}{4}\right]=0\)
\(\left(x+2\right)\left[\left(x-\frac{1}{2}\right)^2+\frac{7}{4}\right]=0\)
Mà \(\left(x-\frac{1}{2}\right)^2\ge0\)
\(\Rightarrow\left(x-\frac{1}{2}\right)^2+\frac{7}{4}\ge\frac{7}{4}\)
\(\Rightarrow\left(x-\frac{1}{2}\right)^2+\frac{7}{4}>0\)
\(\Rightarrow x+2=0\)
\(\Rightarrow x=-2\)
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