b) ($5^{19}$:$5^{17}$-4) : 7
=(5²-4) : 7
=(25-4) : 7
=21 : 7
=3
c) 295 - (31 - 2² . 5)²
= 295 - (31 - 4 . 5)²
=295 - (31 - 20)²
=295-11²
=296-121
=175
d) 20 : 2² - $5^{9}$:$5^{8}$
=20 : 4-5
=5-5
=0
e) 47-(45 . $2^{4}$- 5² . 12) : 14
=47-(45 . 16- 25 . 12) : 14
=47-(720 -300) : 14
=47-420 : 14
=47-30
=17
f) 10² - 60 : ($5^{6}$ : $5^{4}$ - 3.5)
=100-60 : (5² - 15)
=100-60 : (25 - 15)
=100-60 : 10
=100-6
=94