\(x^2+y^2+z^2+2xy+2yz+2xz-\left(9y^2-12yz+4z^2\right)\)
\(=\left(x+y+z\right)^2-\left(3y-2z\right)^2\)
\(=\left(x+y+z-3y+2z\right)\left(x+y+z+3y-2z\right)\)
\(=\left(x-2y+3z\right)\left(x+4y-z\right)\)
\(x^3-8+x^2-2x=0\)
\(\Leftrightarrow\left(x-2\right)\left(x^2+2x+4\right)-x\left(x-2\right)=0\)
\(\Leftrightarrow\left(x-2\right)\left(x^2+x+4\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-2=0\\x^2+x+4=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=2\\\left(x+\frac{1}{2}\right)^2+\frac{15}{4}=0\left(vn\right)\end{matrix}\right.\)
Ko cần "GP", cảm ơn
Đúng 0
Bình luận (0)
