12. Calculati, folosind proprietatea a^m : a^n = a^m-n
a)8^15: 8^12
b)13^31:13^30+13
c)7^29:7^26-7^2
d)7^17:7^13-7^3+13^0
e)(11+4)^22:15^20-15^0
f)(42:14)^2*9^18:27^6​