1)$\begin{cases}\varrho ^{x-y}=\frac{\sin x}{\sin y} \\ 3.\sqrt{8x^2+3}+1= 6\sqrt{2y^2-2y=1}+8y \end{cases}$2)$\begin{cases}(1+4^{2x-y}).5^{(1-2x+y)}= \\ y^3+4x+1+\ln ({y^2+2x})= 0 \end{cases}$3)$\begin{cases}\sqrt{x^2-2x+6}.\log_3 (6-y)=x \\ \sqrt{y^2-2y+6}.\log_3(6-z)= y \\ \sqrt{z^2-2z+6}.\log_3(6-x)=z\end{cases}$4)...