Question

giúp gấp ạ
câu hỏi: (5x-2)⁴=81
giúp mik tích cho

Answer 1

\(\left(5x-2\right)^4=81\)

=>\(\left(5x-2\right)^4=3^4=\left(-3\right)^4\)

=>\(\left[{}\begin{matrix}5x-2=3\\5x-2=-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}5x=5\\5x=-1\end{matrix}\right.\)

=>\(\left[{}\begin{matrix}x=1\\x=-\dfrac{1}{5}\end{matrix}\right.\)