\(a,\frac{21}{11}\cdot\frac{22}{17}\cdot\frac{68}{63}=\frac{21\cdot22\cdot68}{11\cdot17\cdot63}=\frac{21\cdot11\cdot2\cdot17\cdot4}{11\cdot17\cdot21\cdot3}=\frac{8}{3}\)

\(b,\frac{5}{14}\cdot\frac{7}{13}\cdot\frac{26}{25}=\frac{5\cdot7\cdot26}{14\cdot13\cdot25}=\frac{5\cdot7\cdot13\cdot2}{7\cdot2\cdot13\cdot5\cdot5}=\frac{1}{5}\)

a)  \(\frac{21}{11}\times\frac{22}{17}\times\frac{68}{63}=\frac{21\times22\times68}{11\times17\times63}\)

\(=\frac{21\times2\times11\times4\times17}{11\times17\times3\times21}\)

\(=\frac{8}{3}\)

b)  \(\frac{5}{14}\times\frac{7}{13}\times\frac{26}{25}=\frac{5\times7\times26}{14\times13\times25}\)

\(=\frac{5\times7\times2\times13}{2\times7\times13\times5\times5}\)

\(=\frac{1}{5}\)

anh gửi tin nhắn rồi đó, Ti cK CHO ANH NHA

\(\frac{21}{11}.\frac{22}{17}.\frac{68}{63}=\frac{21.22.68}{11.17.63}=\frac{21.11.2.4.17}{11.17.3.21}=\frac{\left(21.11.17\right).\left(2.4\right)}{\left(11.17.21\right).3}=\frac{2.4}{3}=\frac{8}{3}\)

\(\frac{5}{14}.\frac{7}{13}.\frac{26}{25}=\frac{5.7.26}{14.13.25}=\frac{5.7.13.2}{7.2.13.5.5}=\frac{5.7.13.2}{5.7.13.2.5}=\frac{2}{2.5}=\frac{1}{5}\)

a,= 21x 22x 68/11x 17x 63=21x 11x 2x 17x 4/11x 17x 21x 3=8/3

b,= 5x 7x 26/14x13x25= 5x 7x 13x 2/7x 2x 13x 5x 5

tinh bang cach thuan tien nhat : 2.017 * 35.6 + 63.4 * 2.017 + 2.017 

                            giup mik nha mik sap thi cuoi nam hoc roi

Chúc bn học tốt!