\(\left(\frac{9}{25}\right)^{-x}=\left(\frac{5}{3}\right)^{-6}\)
\(=>\left(\frac{3}{5}\right)^{-2x}=\left(\frac{5}{3}\right)^{-6}\)
\(=>\left(\frac{3}{5}\right)^{-2x}=\left(\frac{3}{5}\right)^6\)
\(=>-2x=6\)
\(=>x=-3\)
câu 2.
\(x^2-xy=-18\)
\(=>x\left(x-y\right)=-18\)
\(=>3x=-18\)
\(=>x=-6\)