TA CÓ: A=\(\frac{10^{11}-1}{10^{12}-1}\) > \(\frac{10^{11}-1-9}{10^{12}-1-9}\)= \(\frac{10^{11}-10}{10^{12}-10}\) =\(\frac{10\left(10^{10}-1\right)}{10\left(10^{11}-1\right)}\)
\(\Rightarrow\)A>\(\frac{10^{10}-1}{10^{11}-1}\)=B
VẬY A>B
A =\(\frac{10^{11}}{10^{12}}\)-1 =\(\frac{1}{10}\)-1 B= \(\frac{10^{10}}{10^{11}}\)-1 =\(\frac{1}{10}\)-1
vì \(\frac{1}{10}\) -1 = \(\frac{1}{10}\)-1 nên \(\frac{10^{11}-1}{10^{12}-1}\)= \(\frac{10^{10}-1}{10^{11}-1}\) chúc bạn học tốt