So sánh:

a/  \(A=\dfrac{17^{18}+1}{17^{19}+1};B=\dfrac{17^{17}+1}{17^{18}+1}\)

b/   \(A=\dfrac{10^8-2}{10^8+2};B=\dfrac{10^8}{10^8+4}\)

c/    \(A=\dfrac{20^{10}+1}{20^{10}-1};B=\dfrac{20^{10}-1}{20^{10}-3}\)

GIÚP MÌNH VỚI