a,\(\frac{7}{8}+\frac{3}{5}=\frac{35}{40}+\frac{24}{40}=\frac{35+24}{40}=\frac{59}{40}\)

b, \(\frac{20}{24}:\frac{5}{8}=\frac{20}{24}x\frac{8}{5}=\frac{20x8}{24x5}=\frac{160}{120}=\frac{4}{3}\)

c,\(\frac{8}{3}-\frac{2}{5}x\frac{1}{6}=\frac{8}{3}-\frac{2x1}{5x6}=\frac{8}{3}-\frac{1}{15}=\frac{13}{5}\)

a) 7/8 + 3/5 = 59/40

b) 20/24 : 5/8 = 4/3

c) 8/3 - 2/5 x 1/6 = 8/3 - 1/15 = 13/5

7/8+3/5=35/40+24/40=59/40

20/24:5/8=160/120

8/3-2/*1/6=8/3-2/30=80/30-2/30=78/30

a) 2/3 + 5/2 - 3/4

= 19/6 - 3/4

= 29/12

b) 2/5 x 1/2 : 1/3

= 1/5 x 3

= 3/5 

2/9 : 2/9 x 1/2

= 1 x 1/2 

= 1/2

a) ( 1 1/2 + 2 3/4 ) x 4 3/5

= ( 3/2 + 11/4 ) x 23/5

= 17/4 x 23/5

= 391/20

b) ( 5 2/3 - 4 1/3 ) : 2 1/4

= ( 17/3 - 13/3 ) : 9/4

= 4/3 : 9/4

= 16/27

a. (\(\frac{11}{2}+\frac{23}{4}\)) * 43/5

= 45/4 * 43/5

= 9/4 * 43 = 387/4 = \(96\frac{3}{4}\)

b. (52/3-41/3) * 21/4

= 11/3  : 21/4

 = 11/3 * 4/21 = 44/63 

a). ( 1 1/2 + 2 3/4) x 4 3/5

 = ( 3/2+11/4) x 23/5

= 17/4 x 23/5

=391/20

b).( 5 2/3 - 4 1/3 ) : 2 1/4

=(17/3-13/3):9/4

=4/3 : 9/4

=16/27

a: \(=\dfrac{-3-5-7}{4}=\dfrac{-15}{4}\)

b: \(=\dfrac{-6-5-2+6}{11}=\dfrac{-7}{11}\)

623/12

1/15

5/12

2/7

4/15

1/4

=1/4

7/9

4/21

3/4

7/ 9                                    4/21                                          và 3/4 nha

a.\(\frac{2}{9}+x=1\)

\(x=1-\frac{2}{9}\)

\(x=\frac{11}{9}\)

b.\(\frac{6}{7}-x=\frac{2}{3}\)

\(x=\frac{6}{7}-\frac{2}{3}\)

\(x=\frac{4}{21}\)

c.\(x-\frac{1}{2}=\frac{1}{4}\)

\(x=\frac{1}{4}+\frac{1}{2}\)

\(x=\frac{3}{4}\)

\(a;\frac{3}{7}+\frac{2}{3}=\frac{9}{21}+\frac{14}{21}=\frac{23}{21}\)

\(b;\frac{8}{7}-\frac{12}{28}\times\frac{7}{3}=\frac{8}{7}-\frac{3}{7}\times\frac{7}{3}=\frac{8}{7}-1=\frac{8}{7}-\frac{7}{7}=\frac{1}{7}\)

\(c;\frac{5}{6}\times3=\frac{15}{6}=\frac{5}{2}\)

\(d;\frac{3}{2}:\frac{7}{15}=\frac{3}{2}\times\frac{15}{7}=\frac{45}{14}\)

a) 3/7+2/3=9/21+14/21=23/21

b) 8/7-12/28*7/3=8/7-1=8/7-7/7-1/7

c) 5/6*3=5/2

d) 3/2:7/15=3/2*15/7=45/14

\(\left(x+\frac{1}{3}\right)\left(\frac{3}{4}-2x\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x+\frac{1}{3}=0\\\frac{3}{4}-2x=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{-1}{3}\\x=\frac{3}{8}\end{cases}}\)

Vậy \(x\in\left\{\frac{-1}{2};\frac{3}{8}\right\}\)

Làm đầy đủ hộ mình đi được k bạn

\(a,1\frac{1}{3}+\frac{2}{3}x=5\frac{1}{3}\)

\(\Rightarrow\frac{4}{3}+\frac{2}{3}x=\frac{16}{3}\)

\(\Rightarrow\frac{2}{3}x=\frac{16}{3}-\frac{4}{3}\)

\(\Rightarrow\frac{2}{3}x=4\)

\(\Rightarrow x=4:\frac{2}{3}=4.\frac{3}{2}=6\)

Vậy x=6

\(b,\left(x+\frac{1}{3}\right)\left(\frac{3}{4}-2x\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x+\frac{1}{3}=0\\\frac{3}{4}-2x=0\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}x=\frac{-1}{3}\\-2x=\frac{3}{4}\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}x=\frac{-1}{3}\\x=\frac{-3}{8}\end{cases}}\)

Vậy.................

\(c,\frac{-4}{5}x+1\frac{1}{3}x=-1\frac{1}{3}\)

\(\Rightarrow\frac{-4}{5}x+\frac{4}{3}x=\frac{-4}{3}\)

\(\Rightarrow\frac{-2}{3}x=\frac{-4}{3}\)

\(\Rightarrow x=\frac{-4}{3}:\frac{-2}{3}=\frac{-4}{3}.\frac{3}{-2}=2\)

Vậy x=2