\(\frac{5}{9}\times\frac{8}{17}+\frac{4}{9}\times\frac{8}{17}\)

\(=\left(\frac{5}{9}+\frac{4}{9}\right)\times\frac{8}{17}\)

\(=1\times\frac{8}{17}\)

\(=\frac{8}{17}\)

      \(\frac{5}{9}x\frac{8}{17}+\frac{4}{9}x\frac{8}{17}\)

\(=\frac{8}{17}x\left(\frac{5}{9}+\frac{4}{9}\right)\)

\(=\frac{8}{17}x\frac{9}{9}\)

\(=\frac{8}{17}x1\)

\(=\frac{8}{17}\)

5/9 x 8/17 + 4/9 x 8/17 

= ( 5/9 + 4/9 ) x 8/17 

= 1 x 8/17 

= 8/17 

\(\frac{5}{5}x\)\(\frac{17}{21}+\frac{17}{21}x\)\(\frac{2}{5}\)

=(\(\frac{5}{5}+\frac{2}{5}\)) x\(\frac{17}{21}\)

=\(\frac{7}{5}x\)\(\frac{17}{21}\)

\(\frac{119}{105}\)

ko hiểu

 7/5x17/21=17/15 mới đúng

12/17+8/17=20/17+19/17=39/17

12/15 + 37/7 + 16/5 + 5/7 = 10

12/15 + 37/7 + 16/5 + 5/7

= 4/5 + 37/7 + 16/5 + 5/7

= (4/5 + 16/5) + (37/7 + 5/7)

= 4 + 6

= 10

Chúc bạn học tốt.

😁😁😁

12/15 + 37/7 + 16/5 + 5/7

= ( 37/7 + 5/7 ) + ( 12/15 + 16/5 )

= 6 + ( 12/15 + 48/15 )

= 6 + 4 

= 10

Bổ ích thì k cho c em nha!

22/11.22/17.68/63=8/3

\(\frac{21}{11}\times\frac{22}{17}\times\frac{68}{63}\)

Bạn ơi nhớ ghi gì nha

\(\frac{21}{11}\times\frac{22}{17}\times\frac{68}{63}=\frac{8}{3}\)

\(\frac{15}{34}-\frac{5}{17}+\frac{19}{34}-\frac{12}{17}\)

\(=\left(\frac{15}{34}+\frac{19}{34}\right)-\left(\frac{5}{17}+\frac{12}{17}\right)\)

\(=1-1=0\)

\(\frac{15}{34}-\frac{5}{17}+\frac{19}{34}-\frac{12}{17}\)

\(=\left(\frac{15}{34}+\frac{19}{34}\right)-\left(\frac{5}{17}+\frac{12}{17}\right)\)

\(=\frac{34}{34}-\frac{17}{17}\)

\(=1-1\)

\(=0\)

\(\frac{15}{34}-\frac{5}{17}+\frac{19}{34}-\frac{12}{17}\)

=\(\frac{15}{34}+\frac{19}{34}-\frac{5}{17}-\frac{12}{17}\)

=\(1-\frac{5}{17}-\frac{12}{17}\)

=\(1-\left(\frac{5}{17}+\frac{12}{17}\right)\)

=\(1-1\)

=\(0\)

Đầu đề hơi sai 

a,Ta có: \(1-\frac{17}{19}=\frac{2}{19}\) và \(1-\frac{15}{17}=\frac{2}{17}\)

Vì \(\frac{2}{19}< \frac{2}{17}\) nên \(\frac{17}{19}< \frac{15}{17}\)

a. 17/19 = 19/19 -2/19 = 1- 2/19

15/17 = 17/17 - 2/17 = 1 - 2/17

Vì 2/17 >2/19 nên 1-2/17 < 1 - 1/19

hay 15/17 < 17/19

mình sẽ  giải cho bạn nhưng mình ko phải là  khoa  mà là quan anh bạn của khoa

45 x 16 - 17 / 45 x 15 + 28 = 45 x ( 15 + 1 ) - 17 = 45 x 15 + 45 - 17 / 45 x 15 + 28= 45 x 15 + 28 / 45 x 15 + 28=1

45.16-17/45.15+28

=45.15+(45-17)/45.15+28

=45.15+28/45.15+28

=1

\(\frac{45\cdot16-17}{45\cdot15+28}\)

\(=\frac{45\cdot15+45-17}{45\cdot15+28}\)

\(=\frac{45\cdot15+28}{45\cdot15+28}\)

\(=1\)

\(=\dfrac{5}{12}+\left(\dfrac{8}{17}+\dfrac{60}{17}\right)\\ =\dfrac{5}{12}+4=4\dfrac{5}{12}\)

=512+(817+6017)=512+4=4512

5/12 + 8/17 + 60/17

= 5/12 + 68/7

= 5/12 + 4/1

= 5/12 + 48/12

= 53/12

HT