a) 15/3 x 7/5 + 7/5 x 10/3 + 7/5

= (15/3 + 10/3  + 1) x 7/5

= 28/3 x 7/5

= 196/15

c) 2009 + 3567 + 6433 - 1009

= (2009 - 1009 ) + (3567 + 6433)

= 1000 + 10000

= 11000

\(\frac{15}{3}\)x\(\frac{7}{5}+\frac{7}{5}\)x\(\frac{10}{3}+\frac{7}{5}\)

= \(\frac{15}{3}\)x \(\frac{7}{5}+\frac{7}{5}\)x \(\frac{10}{3}+\frac{7}{5}x1\)

=\(\left(\frac{15}{3}+\frac{10}{3}+1\right)\)x \(\frac{7}{5}\)

= \(\frac{100}{3}\)x \(\frac{7}{5}\)

=\(\frac{140}{3}\)

\(\frac{1212}{1717}\)x \(\frac{165165}{132132}\)x\(\frac{515151}{515151}\)

= \(\frac{12}{17}\)x \(\frac{165}{132}\)x \(\frac{51}{51}\)

= \(\frac{12}{17}\)x\(\frac{165}{132}\)x 1

= \(\frac{165}{187}\)

2009 + 3567 + 6433 - 1009

= ( 2009 - 1009 ) + (3567 +6433 )

=1000 + 10000

= 11000

phần b mk ko chắc lắm đâu

Đường chéo thứ 2 có là :

   27 x 2/3 = 18 ( cm ) 

Diện tích hình thoi là :

 ( 27 x 18 ) : 2 = 243 ( cm2 ) 

     Đáp số : 243 cm2 

tk ủng hộ mk nha ạ !!!!!!!!!

Tk mình đi mọi người mình bị âm nè!

Ai tk mình mình tk lại cho!

 a,  \(\dfrac{5\times11\times15\times18}{6\times15\times22\times10}\)

= \(\dfrac{5\times11\times15\times6\times3}{6\times15\times11\times2\times2\times5}\)

= \(\dfrac{5\times11\times15\times6}{5\times11\times15\times6}\) \(\times\) \(\dfrac{3}{2\times2}\)

= 1 \(\times\) \(\dfrac{3}{4}\)

= \(\dfrac{3}{4}\)

b, \(\dfrac{7}{12}\) \(\times\) \(\dfrac{3}{5}\) + \(\dfrac{3}{5}\) \(\times\) \(\dfrac{5}{12}\)

= \(\dfrac{3}{5}\) \(\times\) ( \(\dfrac{7}{12}+\dfrac{5}{12}\))

= \(\dfrac{3}{5}\) \(\times\) \(\dfrac{12}{12}\)

= \(\dfrac{3}{5}\) \(\times\) 1 

= \(\dfrac{3}{5}\)

\(a,\dfrac{5}{13}\times\dfrac{4}{15}\times13=\dfrac{5\times4\times13}{13\times5\times3}=\dfrac{4}{3}\\ b,\left(\dfrac{3}{7}+\dfrac{5}{2}\right)\times\dfrac{7}{5}=\dfrac{3}{7}\times\dfrac{7}{5}+\dfrac{5}{2}\times\dfrac{7}{5}=\dfrac{3}{5}+\dfrac{7}{2}=\dfrac{6}{10}+\dfrac{35}{10}=\dfrac{41}{10}\\ c,\dfrac{1}{5}\times\dfrac{11}{18}+\dfrac{11}{18}\times\dfrac{3}{5}=\dfrac{11}{18}\times\left(\dfrac{1}{5}+\dfrac{3}{5}\right)=\dfrac{11}{18}\times\dfrac{4}{5}=\dfrac{22}{45}\)

a, 4/3  b, 41/10   c,22/45

A) 5/4 x X = 3/8 + 5/12

5/4 x X = 19/24

        X  = 19/24 : 5/4

        X  = 19/30

vậy x =...

B, 3 x 7/10 + 7/10 x 5 + 2 x 7/10

  = 7/10 x ( 3 + 5 + 2)

  = 7/10 x 10

  = 7

Giúp tớ với mọi người ơi

\(A=\frac{1}{2}×\frac{3}{4}+\frac{1}{4}×\frac{1}{2}\)

\(A=\frac{1}{2}×\left(\frac{3}{4}+\frac{1}{4}\right)\)

\(A=\frac{1}{2}×\left(\frac{3+1}{4}\right)\)

\(A=\frac{1}{2}×1\)

\(A=\frac{1}{2}\)

\(B=\frac{1212}{2121}×\frac{151515}{161616}\)

\(B=\frac{1212:101}{2121:101}×\frac{151515:10101}{161616:10101}\)

\(B=\frac{12}{21}×\frac{15}{16}\)

\(B=\frac{12×15}{21×16}\)

\(B=\frac{3×4×3×5}{3×7×4×4}\)

\(B=\frac{15}{28}\)