Question

Huhu help

(x^2+7)(x^2-27) = 0

Answer 1

Vì : \(\left(x^2+7\right)\left(x^2-27\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x^2+7=0\\x^2-27=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x^2=-7\Rightarrow x\in\varphi\\x^2=27\Rightarrow x\in\varphi\end{cases}}}\)

Vậy ...

Answer 2

\(\left(x^2+7\right)\left(x^2-27\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x^2+7=0\\x^2-27=0\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x^2=-7\left(vl\right)\\x^2=27\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=\sqrt{27}\\x=-\sqrt{27}\end{cases}}\)

vậy \(x=\sqrt{27}\) hay \(x=-\sqrt{27}\)