Aloha :)
$$\left.1024=4\cdot L^{0,5}\cdot L^{0,75}\cdot16^{0,75}\quad\right|\quad:4$$$$\left.256=L^{0,5}\cdot L^{0,75}\cdot16^{0,75}\quad\right|\quad\text{Exponenten addieren}$$$$\left.256=L^{0,5+0,75}\cdot16^{0,75}\quad\right.$$$$\left.256=L^{1,25}\cdot16^{0,75}\quad\right|\quad1,25=\frac{5}{4}\;\;;\;\;0,75=\frac{3}{4}$$$$\left.256=L^{\frac{5}{4}}\cdot16^{\frac{3}{4}}\quad\right|\quad(\cdots)^4$$$$\left.256^4=\left(L^{\frac{5}{4}}\cdot16^{\frac{3}{4}}\right)^4=\left(L^{\frac{5}{4}}\right)^4\cdot\left(16^{\frac{3}{4}}\right)^4=L^{\frac{5}{4}\cdot4}\cdot16^{\frac{3}{4}\cdot4}=L^5\cdot16^3\quad\right|\quad:16^3$$$$\left.\frac{256^4}{16^3}=L^5\quad\right|\quad\text{beide Seiten vertauschen}$$$$\left.L^5=\frac{256^4}{16^3}=\frac{(16^2)^4}{16^3}=\frac{16^8}{16^3}=16^5\quad\right|\quad(\cdots)^{1/5}$$$$\left.(L^5)^{1/5}=(16^5)^{1/5}\quad\right.$$$$L=16$$