ta có: \(M=\frac{7.9+14.27+21.36}{21.27+42.81+63.108}\)
\(M=\frac{7.9+7.2.9.3+7.3.9.4}{21.27+21.227.3+21.3.27.4}\)
\(M=\frac{7.9.\left(1+2.3+3.4\right)}{21.27.\left(1+2.3+3.4\right)}\)
\(M=\frac{7.9}{3.7.3.9}\)
\(M=\frac{1}{3^2}\)
\(M=\frac{1}{9}\)
và \(N=\frac{37}{333}=\frac{37}{37.9}=\frac{1}{9}\)
\(N=\frac{1}{9}\)
\(\Rightarrow M=N\left(=\frac{1}{9}\right)\)
M= \(\frac{7.9+14.27+21.36}{21.27+42.81+63.108}\).
M= \(\frac{7.9+14.27+21.36}{7.3.9.3+14.3.27.3+21.3+36.3}\).
M= \(\frac{7.9+14.27+21.36}{7.9.9+14.27.9+21.36.9}\).
M= \(\frac{7.9+14.27+21.36}{9\left(7.9+14.27+21.36\right)}\).
M= \(\frac{1}{9}\).
Ta có: N= \(\frac{37}{333}\)= \(\frac{1}{9}\).
Vì \(\frac{1}{9}\)= \(\frac{1}{9}\) nên M= N.
Vậy M= N.