Giúp tớ vớiiiiii

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

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

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

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

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

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

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

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

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

5/9 x 8/17 + 4/9 x 8/17 

= ( 5/9 + 4/9 ) x 8/17 

= 1 x 8/17 

= 8/17 

a) 3/8 x 14/53 x 8/3

=3/8x8/3x14/53

=     1    x 14/53

=14/53

b) 9/17x1/5+9/17x4/5

=9/17x(1/5+4/5)

=9/17x     5/5

=9/17x1

=   9/17

Li-ke cho mik nhé!

= \(\frac{3}{8}\cdot\frac{14}{53}\cdot\frac{8}{3}=\frac{14}{53}\cdot1=\frac{14}{53}\)

dấu . là dấu nhân nha

\(=\frac{9}{17}\cdot\frac{1}{5}+\frac{9}{17}\cdot\frac{4}{5}=\frac{9}{17}\cdot\left(\frac{1}{5}+\frac{4}{5}\right)=\frac{9}{17}\cdot1=\frac{9}{17}\)

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

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

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

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

ko hiểu

 7/5x17/21=17/15 mới đúng

812 x 5 + 812 x 7 - 7 - 812 x 2 ???

 toàn câu hỏi sai

=1500

Tính nhanh :

    9 x 8 x 15 / 12 x 6 x 5 = ( 9 x 6 ) x ( 8 x 5 ) x 15 / 12

                                     =     36     x     40     x 15 / 12

                                     =           1440           x 15 / 12

                                     =               21600 / 17280

                    Đáp số : 21600 / 17280.( mình chưa chắc ! )

Không phải lời giải đâu

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\(\frac{1}{7}x\frac{3}{5}+\frac{3}{5}x\frac{1}{2}+\frac{3}{5}\)

\(=\frac{3}{5}.\left(\frac{1}{7}+\frac{1}{2}+1\right)\)

\(=\frac{3}{5}x\left(\frac{2}{14}+\frac{7}{14}+\frac{14}{14}\right)\)

\(=\frac{3}{5}x\frac{23}{14}\)

\(=\frac{69}{70}\)

Tham khảo nha !!!