Ta có: C = (1.5.6+2.10.12+4.20.24+..+9.45.54):(1.3.5+2.6.10+4.12.20+...+9.27.45)
= (1.3.5.2+2.6.10.2+4.12.20.2+...+9.27.45.2):(1.3.5+2.6.10+4.12.20+...+9.27.45)
= (2.(1.3.5+2.6.10+4.12.20+...+9.27.45)):(1.3.5+2.6.10+4.12.20+...+9.27.45)
=2
Bằng 2 bạn nhé
k cho mk dc k.đi..................................................