Aloha :)
Willkommen in der Mathelounge... \o/
$$\left.5\cdot(1,6\cdot x^{-0,2}\cdot y^{0,2})=8\cdot(2\cdot x^{0,8}\cdot0,2\cdot y^{-0,8})\quad\right|\text{Zahlen multiplizieren}$$$$\left.8\cdot x^{-0,2}\cdot y^{0,2}=8\cdot0,4\cdot x^{0,8}\cdot y^{-0,8}\quad\right|\,:\,8$$$$\left. x^{-0,2}\cdot y^{0,2}=0,4\cdot x^{0,8}\cdot y^{-0,8}\quad\right|\cdot y^{0,8}$$$$\left. x^{-0,2}\cdot y^{0,2}\cdot y^{0,8}=0,4\cdot x^{0,8}\quad\right|\cdot x^{0,2}$$$$\left. y^{0,2}\cdot y^{0,8}=0,4\cdot x^{0,8}\cdot x^{0,2}\quad\right|a^b\cdot a^c=a^{b+c}$$$$\left. y^{0,2+0,8}=0,4\cdot x^{0,8+0,2}\quad\right|\text{Exponenten ausrechnen}$$$$\left. y=0,4\cdot x\quad\right.$$