Ta có: \(7\cdot6^{10}\cdot2^{21}\cdot3^6-2^{19}\cdot6^{15}\)
\(=7\cdot3^{10}\cdot2^{10}\cdot2^{21}\cdot3^6-2^{19}\cdot3^{15}\cdot2^{15}\)
\(=7\cdot2^{31}\cdot3^{16}-2^{34}\cdot3^{15}\)
\(=2^{31}\cdot3^{15}\left(7\cdot3-2^3\right)=2^{31}\cdot3^{15}\cdot13\)
Ta có: \(9\cdot6^{15}\cdot2^{13}-4\cdot3^{15}\cdot2^{26}\)
\(=3^2\cdot3^{15}\cdot2^{15}\cdot2^{13}-2^2\cdot3^{15}\cdot2^{26}\)
\(=3^{17}\cdot2^{28}-3^{15}\cdot2^{28}=3^{15}\cdot2^{28}\left(3^2-1\right)=3^{15}\cdot2^{31}\)
Ta có: \(B=\frac{7\cdot6^{10}\cdot2^{21}\cdot3^6-2^{19}\cdot6^{15}}{9\cdot6^{15}\cdot2^{13}-4\cdot3^{15}\cdot2^{26}}\)
\(=\frac{2^{31}\cdot3^{15}\cdot13}{3^{15}\cdot2^{31}}=13\)
