\(\frac{2.6.12+6.12.20+12.21.32}{3.8.15+9.16.25+18.28.40}\)

\(=\frac{12.\left(12+120+672\right)}{3.\left(120+1200+6720\right)}\)

\(=\frac{12.\left(12+120+672\right)}{30\left(12+120+672\right)}\)

\(=\frac{12}{30}\)

\(=\frac{2}{5}\)

\(\frac{2.6.12+6.12.20+12.21.32}{3.8.15+9.16.25+18.28.40}\)

=\(\frac{2.6.12+6.12.2.10+12.3.7.4.8}{3.8.15+9.2.8.5.5+9.2.28.40}\)

=\(\frac{144+144.10+144.56}{360+360.10+360.56}\)

=\(\frac{144\left(1+10+56\right)}{360\left(1+10+56\right)}\)

=\(\frac{144.67}{360.67}\)

=\(\frac{72.2.67}{72.5.67}\)

=\(\frac{2}{5}\)

Ta có: \(\frac{2\cdot6\cdot12+6\cdot12\cdot20+12\cdot21\cdot32}{3\cdot8\cdot15+9\cdot16\cdot25+18\cdot28\cdot40}\)

\(=\frac{2^2\cdot6^2+2^2\cdot6^2\cdot10+2^2\cdot6^2\cdot7\cdot2^3}{3^2\cdot8\cdot5+3^2\cdot8\cdot5\cdot10+3^2\cdot8\cdot5\cdot56}\)

\(=\frac{2^2\cdot6^2\left(1+10+56\right)}{3^2\cdot8\cdot5\left(1+10+56\right)}=\frac{2^2\cdot6^2}{3^2\cdot8\cdot5}\)

\(=\frac{2^2\cdot3^2\cdot2^2}{3^2\cdot2^3\cdot5}=\frac{2^4}{2^3\cdot5}=\frac{2^3\cdot2}{2^3\cdot5}=\frac{2}{5}\)

\(\frac{2.6.12}{3.8.15}=\frac{2.3.4}{3.4.3}=\frac{2}{3}\)

Các phân số kia rút gọn cũng vậy.

Vậy kết quả = \(\frac{2}{3}\)

ket qua la 2/3

 ai đi qua mình tích lại cho 2 tích luôn nhé

a)10368

b)24120

A = 2002 2000.16 − 1970 = 2002 ( 2002 − 2 ) .16 − 1970 = 2002 2002. ( 16 − 1 ) = 1 15

và  B = 12.3 + 2.4.6 + 4.8.12 + 7.14.21 1.3.6 + 2.6.12 + 4.12.24 + 7.21.42 = 12.3 + 2.4.6 + 4.8.12 + 7.14.21 1.3.2.3 + 2.6.3.4 + 4.12.3.8 + 7.21.14.3 = 12.3 + 2.4.6 + 4.8.12 + 7.14.21 3. ( 12.3 + 2.4.6 + 4.8.12 + 7.14.21 ) = 1 3 = 5 15

Vậy B > A

\(\frac{1.2.3+2.4.6+3.6.9+5.10.15}{1.3.6+2.6.12+3.9.18+5.15.30}\)

\(=\frac{1.2.3.\left(1+2+3+5\right)}{1.3.6.\left(1+2+3+5\right)}\)

\(=\frac{1.2.3.5}{1.3.6.5}\)

\(=\frac{1}{3}\)

Ta có 1008. 8 – 994 = 1008. 7 + 1008 – 994

            = 1008. 7 + 14

            = 7. (1008 + 2) = 7. 1010

Vậy C = 1010/(7.1010) = 1/7