\(128\times\left(\frac{3}{2x}-\frac{1}{4}\right)^3=-250.\)
\(\left(\frac{3}{2x}-\frac{1}{4}\right)^3=-250\div128\)
\(\left(\frac{3}{2x}-\frac{1}{4}\right)^3=\frac{125}{64}\)
\(\left(\frac{3}{2x}-\frac{1}{4}\right)^3=\left(\frac{5}{4}\right)^3\)
\(\Rightarrow\frac{3}{2x}-\frac{1}{4}=\frac{5}{4}\)
\(\Rightarrow\frac{3}{2x}=\frac{5}{4}+\frac{1}{4}\)
\(\Rightarrow\frac{3}{2x}=\frac{3}{2}\)
\(\Rightarrow2x=2\)
\(\Rightarrow x=1\)
\(128x\left(\frac{3}{2}X-\frac{1}{4}\right)^3=-250\)
\(\left(=\right)\left(\frac{3}{2}X-\frac{1}{4}\right)^3=-250:128\)
\(\left(=\right)\left(\frac{3}{2}X-\frac{1}{4}\right)^3=-\frac{125}{64}\)
\(\left(=\right)\left(\frac{3}{2}X-\frac{1}{4}\right)^3=\left(-\frac{5}{4}\right)^3\)
\(\left(=\right)\frac{3}{2}X-\frac{1}{4}=-\frac{5}{4}\)
\(\left(=\right)\frac{3}{2}X=-\frac{5}{4}+\frac{1}{4}\)
\(\left(=\right)\frac{3}{2}X=-\frac{4}{4}\)
\(\left(=\right)\frac{3}{2}X=-1\)
\(\left(=\right)X=-1:\frac{3}{2}\)
\(\left(=\right)X=-\frac{2}{3}\)
Vậy \(X=-\frac{2}{3}\)