Question

Answer 1

a) \(\left(5x+3\right)\left(x^2-9\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}5x+3=0\\x^2-9=0\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{3}{5}\\x^2=9\end{matrix}\right.\)  \(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{3}{5}\\x=3\\x=-3\end{matrix}\right.\)

b) \(\left(x^2+2\right)\left(4x-\dfrac{8}{11}\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x^2+2=0\left(vô.lý\right)\\4x-\dfrac{8}{11}=0\end{matrix}\right.\) \(\Leftrightarrow4x=\dfrac{8}{11}\Leftrightarrow x=\dfrac{2}{11}\)

 

Answer 2

@haiyuan