Question

( 3-2/5x) mũ 2 = (-4) mũ 2

Answer 1

\(\left(3-\frac{2}{5}x\right)^2=\left(-4\right)^2\\ \left(3-\frac{2}{5}x\right)^2=4^2=\left(-4\right)^2\\ \Rightarrow\left[{}\begin{matrix}3-\frac{2}{5}x=4\\3-\frac{2}{5}x=-4\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}\frac{2}{5}x=-1\\\frac{2}{5}x=7\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{-5}{2}\\x=\frac{35}{2}\end{matrix}\right.\)

Vậy \(x\in\left\{\frac{-5}{2};\frac{35}{2}\right\}\)