<=> x4+3x3=14x2+6x-4
\(\Leftrightarrow x^4+3x^3-\frac{7}{4}x^2-6x+4=\frac{49}{4}x^2\)
\(\Leftrightarrow\left(x^2+\frac{3}{2}x-2\right)^2=\frac{49}{4}x^2\)
\(\Leftrightarrow\left(x^2+\frac{3}{2}x-2\right)^2-\frac{49}{4}x^2=0\)
\(\Leftrightarrow\left(x^2+\frac{3}{2}x-2+\frac{7}{2}x\right)\left(x^2+\frac{3}{2}x-2-\frac{7}{2}x\right)=0\)
\(\Leftrightarrow\left(x^2+5x-2\right)\left(x^2-2x-2\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x^2+5x-2=0\\x^2-2x-2=0\end{cases}}\)
Đến đây bn tự làm tiếp nha
tk mk vs