[tex]\displaystyle\bf\\\left(-\frac{2}{3}\right)^{4}:\left(-\frac{2}{3}\right)^{x}=-\frac{2}{3}\\\\\\\left(-\frac{2}{3}\right)^{4}:\left(-\frac{2}{3}\right)^{x}=\left(-\frac{2}{3}\right)^{1}\\\\\\\left(-\frac{2}{3}\right)^{4-x}=\left(-\frac{2}{3}\right)^{1}\\\\\\4-x=1\\\\x=4-1\\\\\boxed{\bf~x=3\in~N}[/tex]
