a)5^140:25^70+8^32:16^24+100^25:10^48-2^2x5^2=
= 5^140:5^140+2^96:2^96+10^50:10^48-4×25 =
= 1 + 1 + 10^2 - 100 =
= 2 + 100 - 100 =
= 2
b)(7^11)^13x(7^13)^7:(7^18)^13x7^2+1^2017-2^1x5^2=
= 7^143 × 7^91 : 7^234 × 7^2 + 1 - 2 × 25 =
= 7^234 : 7^234 × 49 + 1 - 50 =
= 1 × 49 + 1 - 50 =
= 50 - 50 =
= 0