$\text{a)}\left|7,5\right|=7,5$  

$\text{b)}\left|-7\right|=7$  

$\text{c)}\left|0\right|=0$  

$\text{d)}\left|3-5\right|-2\cdot \left|1-3\right|=\left|-2\right|-2\cdot \left|-2\right|=2-2\cdot 2=2-4=-2$  

$\text{e)}\left|2-\right|2-5\left|\left|=\right|2-\right|-3\left|\left|=\right|2-3\right|=\left|-1\right|=1$  

$\text{f)}\left|1-\right|3+2\left|\left|=\right|1-\right|5\left|\left|=\right|1-5\right|=\left|-4\right|=4$