1.
a;
\(x^4+3x^3+4x^2+3x+1=0\)
\(\Leftrightarrow x^4+x^3+2x^3+2x^2+2x^2+2x+x+1=0\)
\(\Leftrightarrow\left(x+1\right)\left(x^3+2x^2+2x+1\right)=0\)
\(\Leftrightarrow\left(x+1\right)\left(x+1\right)\left(x^2+x+1\right)=0\)
Vì x2 + x + 1 >0 nên (x+1)2 =0
=>x=-1
b;
\(2x^2+3x-5=0\)
\(\Leftrightarrow2\left(x-1\right)\left(x+2,5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\\x+2,5=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-2,5\end{matrix}\right.\)
Đúng 0
Bình luận (0)
