so sánh: A với B, C với D, E với F
a,A=\(\frac{10^{19}+1}{10^{20}+1}\) B=\(\frac{10^{20}+1}{10^{21}+1}\)
b, C=\(\frac{9^{2015}+3}{9^{2014}+3}\) D= \(\frac{2^{2016}+3}{2^{2015}+3}\)
c E=\(\frac{20^{10}+1}{20^{10}-1}\) F=\(\frac{20^{10}-1}{20^{10}-3}\)