7x1=7

7x2=14

7x3=21

7x4=28

7x5=40

7x6=42

7x7=49

7x8=56

7x9=63

7x10=70

7x1=7

7x2=14

7x3=21

7x4=28

7x5=35

7x6=42

7x7=49

7x8=56

7x9=63

7x10=70

7×1=7

7×2=14

7×3=21

7×4=28

7×5=35

7×6=42

7×7=49

7×8=56

7×9=63

7×10=70

<tích cho mk nhé>

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\(=\dfrac{3}{7}\times\left(\dfrac{1}{5}+\dfrac{2}{3}-\dfrac{1}{8}\right)\\ =\dfrac{3}{7}\times\left(\dfrac{24}{5\times24}+\dfrac{2\times40}{3\times40}-\dfrac{15}{8\times15}\right)\\ =\dfrac{3}{7}\times\left(\dfrac{24+80-15}{120}\right)\\ =\dfrac{3}{7}\times\dfrac{89}{120}\\ =\dfrac{89}{280}\)

\(\dfrac{3}{7}\times\dfrac{1}{5}+\dfrac{2}{3}\times\dfrac{3}{7}-\dfrac{3}{7}\times\dfrac{1}{8}\)
\(=\dfrac{3}{7}\times\left(\dfrac{1}{5}+\dfrac{3}{7}-\dfrac{1}{8}\right)\)
\(=\dfrac{3}{7}\times\dfrac{56+120-35}{280}\)
\(=\dfrac{3}{7}\times\dfrac{141}{280}\)
\(=\dfrac{423}{1960}\)

\(A=5x^3-7x^2+3x^3-4x^2+x^2-x^3+5x-1=7x^3-10x^2+5x-1\)

\(B=5x^3+3x^2-7x^4-5x^3+4x^2-x^4+3=-8x^4+7x^2+3\)

\(A=7x^3-10x^2+5x-1\)

\(B=-8x^4+7x^2+3\)

-6/35

1/5x (4/7- 3/7- 1)=1/5x -6/7= -6/35

\(-\dfrac{6}{35}\)

\(\dfrac{1}{5}\times\dfrac{4}{7}+\dfrac{3}{7}\times\dfrac{1}{5}-\dfrac{1}{5}\)

\(=\dfrac{4}{35}+\dfrac{3}{35}-\dfrac{1}{5}\)

\(=\dfrac{7}{35}-\dfrac{1}{5}\)

\(=\dfrac{1}{5}-\dfrac{1}{5}\)

\(=0\)

0

\(\dfrac{2}{3}-\dfrac{3}{8}=\dfrac{16}{24}-\dfrac{9}{24}=\dfrac{7}{24}\)

\(\dfrac{3}{7}\times\dfrac{4}{5}=\dfrac{3\times4}{7\times5}=\dfrac{12}{35}\)

\(\dfrac{2}{5}:\dfrac{2}{3}=\dfrac{2}{5}\times\dfrac{3}{2}=\dfrac{6}{10}=\dfrac{3}{5}\)

a) 2/5 + 3/4 = 23/20 
b) 2/3 - 3/8 = 7/24 
c) 3/7 x 4/5 = 12/35 
d) 2/5 : 2/3 = 3/5 

\(\dfrac{2}{5}+\dfrac{3}{4}=\dfrac{8}{20}+\dfrac{15}{20}=\dfrac{22}{20}=\dfrac{11}{10}\)

\(\dfrac{2}{3}-\dfrac{3}{8}=\dfrac{16}{24}-\dfrac{9}{24}=\dfrac{7}{24}\)

\(\dfrac{3}{7}\times\dfrac{4}{5}=\dfrac{12}{35}\)

\(\dfrac{2}{5}:\dfrac{2}{3}=\dfrac{3}{5}\)

\(\dfrac{2}{5}+\dfrac{3}{4}=\dfrac{8}{20}+\dfrac{15}{20}=\dfrac{23}{20}\)

\(\dfrac{2}{3}-\dfrac{3}{8}=\dfrac{16}{24}-\dfrac{9}{24}=\dfrac{7}{24}\)

\(\dfrac{3}{7}x\dfrac{4}{5}=\dfrac{12}{35}\)

\(\dfrac{2}{5}:\dfrac{2}{3}=\dfrac{2}{5}x\dfrac{3}{2}=\dfrac{3}{5}\)

\(a,\dfrac{9}{5}+\dfrac{2}{5}\times\dfrac{4}{6}=\dfrac{9}{5}+\dfrac{4}{15}=\dfrac{27}{15}+\dfrac{4}{15}=\dfrac{31}{15}\\ b,\dfrac{3}{8}\times2-\dfrac{6}{7}\times\dfrac{1}{3}=\dfrac{3}{4}-\dfrac{2}{7}=\dfrac{21}{28}-\dfrac{8}{28}=\dfrac{13}{28}\)

A)=9/5 + 4/15

=27/15+4/15

=31/15

B)=3/4-2/14

=36/28-4/28

=32/28=?

dễ lắm

3/7\(\times\)(2/5+3/5+1)

=3/7 nhân 2

=6/7