a ) ( x + 1 ) ( x + 2 ) ( x + 3 ) = 0
\(\Leftrightarrow\left[{}\begin{matrix}x+1=0\\x+2=0\\x+3=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=-2\\x=-3\end{matrix}\right.\)
Vậy tập nghiệm của phương trình là \(S=\left\{-1;-2;-3\right\}\)
b ) \(\left(x-1\right)^2-16=0\)
\(\Leftrightarrow\left(x-1\right)^2-4^2=0\)
\(\Leftrightarrow\left(x-1+4\right)\left(x-1-4\right)=0\)
\(\Leftrightarrow\left(x+3\right)\left(x-5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+3=0\\x-5=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=5\end{matrix}\right.\)
Vậy tập nghiệm của phương trình là S = {-3;5}
c ) \(\left(2x-1\right)^2-\left(x+3\right)^2=0\)
\(\Leftrightarrow\left(2x-1-x-3\right)\left(2x-1+x+3\right)=0\)
\(\Leftrightarrow\left(x-4\right)\left(3x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-4=0\\3x+2=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=4\\x=-\dfrac{2}{3}\end{matrix}\right.\)
Vậy ......
a, \(\left[{}\begin{matrix}x+1=0\\x+2=0\\x+3=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=-1\\x=-2\\x=-3\end{matrix}\right.\)
b, \(\left(x-1\right)^2-16=0\Leftrightarrow\left(x-1\right)^2-4^2=0\Leftrightarrow\left(x-5\right)\left(x+3\right)=0\Rightarrow\left[{}\begin{matrix}x-5=0\\x+3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\x=-3\end{matrix}\right.\)
c,\(\Rightarrow\left(x-2\right)\left(3x+4\right)\Rightarrow\left[{}\begin{matrix}x-2=0\\3x+4=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{-4}{3}\end{matrix}\right.\)
