$-72:\left(-63:\left(-7\right)\right)-5$

= $-72:9-5$

= $-8-5$

= $-13$

$-40-\left(-17\right)+81:9$

= $-40+17+9$

= $-23+9$

= $-14$

$\left(-16:\left(-20:\left(-10\right)\right)\right)·\left(6:\left(-3\right)\right)$

= $\left(-16:2\right)·\left(-2\right)$

= $-8·\left(-2\right)$

= $16$

$-81:\left(-9\right)-(-6·\left(-5\right)+5):\left(-7\right)$

= $9-\left(30+5\right):\left(-7\right)$

= $9-35:\left(-7\right)$

= $9+5$

= $14$