Aloha :)
Willkommen in der Mathelounge... \o/
$$\phantom{=}\left(3\frac34-1\frac12-\frac45\right)\cdot\frac{11}{29}=\left(\frac{15}{4}-\frac32-\frac45\right)\cdot\frac{11}{29}=\left(\frac{75}{20}-\frac{30}{20}-\frac{16}{20}\right)\cdot\frac{11}{29}$$$$=\frac{\cancel{29}}{20}\cdot\frac{11}{\cancel{29}}=\frac{11}{20}$$