\(1,\\ x+\dfrac{1}{2}=-\dfrac{5}{3}\\ x=-\dfrac{5}{3}-\dfrac{1}{2}\\ x=-\dfrac{13}{6}\\ Vậyx=-\dfrac{13}{6}\)

\(2,\\ \dfrac{1}{3}-x=\dfrac{3}{5}\\ x=\dfrac{1}{3}-\dfrac{3}{5}\\ x=-\dfrac{4}{15}\\ Vậyx=-\dfrac{4}{15}\)

\(3,\\ 3-4+x=\dfrac{7}{2}\\ -1+x=\dfrac{7}{2}\\ x=\dfrac{7}{2}+1\\ x=\dfrac{9}{2}\\ Vậyx=\dfrac{9}{2}\)

\(4,\\ x-\dfrac{4}{3}=-\dfrac{7}{9}\\ x=-\dfrac{7}{9}+\dfrac{4}{3}\\ x=\dfrac{15}{27}\\ Vậyx=\dfrac{15}{27}\)

\(5,\\ x-\left(-\dfrac{7}{3}\right)=\dfrac{5}{6}\\ x=\dfrac{5}{6}-\dfrac{7}{3}\\ x=-\dfrac{27}{18}\\ Vậyx=-\dfrac{27}{18}\)

\(6,\\ x-\dfrac{1}{5}=\dfrac{9}{10}\\ x=\dfrac{9}{10}+\dfrac{1}{5}\\ x=\dfrac{11}{10}\\ Vậyx=\dfrac{11}{10}\)

\(7,\\ x+\dfrac{5}{12}=\dfrac{3}{8}\\ x=\dfrac{3}{8}-\dfrac{5}{12}\\ x=-\dfrac{1}{24}\\ Vậyx=-\dfrac{1}{24}\)

\(8,\\ x+\dfrac{5}{4}=\dfrac{7}{6}\\ x=\dfrac{7}{6}-\dfrac{5}{4}\\ x=-\dfrac{9}{24}\\ Vậyx=-\dfrac{9}{24}\)

\(9,\\ x-\dfrac{2}{7}=\dfrac{1}{35}\\ x=\dfrac{1}{35}+\dfrac{2}{7}\\ x=\dfrac{11}{35}\\ Vậyx=\dfrac{11}{35}\\ 10,\\ x-\dfrac{1}{5}=-\dfrac{7}{10}\\ x=-\dfrac{7}{10}+\dfrac{1}{5}\\ x=-\dfrac{1}{2}\\ Vậyx=-\dfrac{1}{2}\)

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Hướng dẫn giải:

a) 5 x (10 + 9)

Cách 1:

5 x (10 + 9) = 5 x 19 = 95

Cách 2:

5 x (10 + 9) = 5 x 10 + 5 x 9 = 50 + 45 = 95

b) 10 x (30 + 5)

Cách 1:

10 x (30 + 5) = 10 x 35 = 350

Cách 2:

10 x (30 + 5) = 10 x 30 + 10 x 5 = 300 + 50 = 350

Hướng dẫn giải nè :

a) 5 x (10 + 9)

Cách 1:

5 x (10 + 9) = 5 x 19 = 95

Cách 2:

5 x (10 + 9) = 5 x 10 + 5 x 9 = 50 + 45 = 95

b) 10 x (30 + 5)

Cách 1:

10 x (30 + 5) = 10 x 35 = 350

Cách 2:

10 x (30 + 5) = 10 x 30 + 10 x 5 = 300 + 50 = 350

Câu 1 : 

a, \(\frac{3\left(2x+1\right)}{4}-\frac{5x+3}{6}=\frac{2x-1}{3}-\frac{3-x}{4}\)

\(\Leftrightarrow\frac{6x+3}{4}+\frac{3-x}{4}=\frac{2x-1}{3}+\frac{5x+3}{6}\)

\(\Leftrightarrow\frac{5x+6}{4}=\frac{9x+1}{6}\Leftrightarrow\frac{30x+36}{24}=\frac{36x+4}{24}\)

Khử mẫu : \(30x+36=36x+4\Leftrightarrow-6x=-32\Leftrightarrow x=\frac{32}{6}=\frac{16}{3}\)

tương tự 

\(\frac{19}{4}-\frac{2\left(3x-5\right)}{5}=\frac{3-2x}{10}-\frac{3x-1}{4}\)

\(< =>\frac{19.5}{20}-\frac{8\left(3x-5\right)}{20}=\frac{2\left(3-2x\right)}{20}-\frac{5\left(3x-1\right)}{20}\)

\(< =>95-24x+40=6-4x-15x+5\)

\(< =>-24x+135=-19x+11\)

\(< =>5x=135-11=124\)

\(< =>x=\frac{124}{5}\)

\(\frac{\left(x-2\right).3}{2}+3+\frac{\left(x-3\right).5}{3}+5+\frac{\left(x-5\right).2}{5}+2=10\)

\(< =>\frac{\left(x-2\right).3.15}{30}+\frac{\left(x-3\right).5.10}{30}+\frac{\left(x-5\right).2.6}{30}=10-2-3-5\)

\(< =>\frac{\left(x-2\right).45+\left(x-3\right).50+\left(x-5\right).12}{30}=0\)

\(< =>45x-90+50x-150+12x-60=0\)

\(< =>107x-300=0< =>x=\frac{300}{107}\)

1/ \(x+\dfrac{1}{2}=\dfrac{-5}{3}\)

\(x=\dfrac{-5}{3}-\dfrac{1}{2}\)

\(x=\dfrac{-10}{6}-\dfrac{3}{6}\)

Vậy \(x=\dfrac{-13}{6}\)

2/\(\dfrac{1}{3}-x=\dfrac{3}{5}\)

\(-x=\dfrac{3}{5}-\dfrac{1}{3}\)

\(-x=\dfrac{9}{15}-\dfrac{5}{15}\)

\(-x=\dfrac{4}{15}\)

Vậy \(x=\dfrac{-4}{15}\)

3/ \(3-4+x=\dfrac{7}{2}\)

\(-4+x=\dfrac{7}{2}-3\)

\(-4+x=\dfrac{7}{2}-\dfrac{6}{2}\)

\(-4+x=\dfrac{1}{2}\)

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

\(x=\dfrac{1}{2}+\dfrac{8}{2}\)

Vậy \(x=\dfrac{9}{2}\)

4/ \(x-\dfrac{4}{3}=\dfrac{-7}{9}\)

\(x=\dfrac{-7}{9}+\dfrac{4}{3}\)

\(x=\dfrac{-7}{9}+\dfrac{12}{9}\)

Vậy \(x=\dfrac{5}{9}\)

5/ \(x-\dfrac{-7}{2}=\dfrac{5}{6}\)

\(x=\dfrac{5}{6}-\dfrac{7}{2}\)

\(x=\dfrac{5}{6}-\dfrac{21}{6}\)

Vậy \(x=\dfrac{-16}{6}=\dfrac{-8}{3}\)

6/ \(x-\dfrac{1}{5}=\dfrac{9}{10}\)

\(x=\dfrac{9}{10}+\dfrac{1}{5}\)

\(x=\dfrac{9}{10}+\dfrac{2}{10}\)

Vậy \(x=\dfrac{11}{10}\)

7/ \(x+\dfrac{5}{12}=\dfrac{3}{8}\)

\(x=\dfrac{3}{8}-\dfrac{5}{12}\)

\(x=\dfrac{9}{24}-\dfrac{10}{24}\)

Vậy \(x=\dfrac{-1}{24}\)

8/ \(x+\dfrac{5}{4}=\dfrac{7}{6}\)

\(x=\dfrac{7}{6}-\dfrac{5}{4}\)

\(x=\dfrac{14}{12}-\dfrac{15}{12}\)

Vậy \(x=\dfrac{-1}{12}\)

9/ \(x-\dfrac{2}{7}=\dfrac{1}{35}\)

\(x=\dfrac{1}{35}+\dfrac{2}{7}\)

\(x=\dfrac{1}{35}+\dfrac{10}{35}\)

Vậy \(x=\dfrac{11}{35}\)

10 /\(x-\dfrac{1}{5}=\dfrac{-7}{10}\)

\(x=\dfrac{-7}{10}+\dfrac{1}{5}\)

\(x=\dfrac{-7}{10}+\dfrac{2}{10}\)

Vậy \(x=\dfrac{-5}{10}=\dfrac{-1}{2}\)

`@` `\text {Ans}`

`\downarrow`

`1)`

\(x+\dfrac{1}{2}=\dfrac{5}{3}\)

`\Rightarrow` \(x=\dfrac{5}{3}-\dfrac{1}{2}\)

`\Rightarrow`\(x=\dfrac{7}{6}\)

Vậy, `x =`\(\dfrac{7}{6}\)

`2)`

\(\dfrac{3}{5}-x=\dfrac{1}{3}\)

`\Rightarrow`\(x=\dfrac{3}{5}-\dfrac{1}{3}\)

`\Rightarrow`\(x=\dfrac{4}{15}\)

Vậy, `x =`\(\dfrac{4}{15}\)

`3)`

\(\dfrac{3}{4}+x=\dfrac{7}{2}\)

`\Rightarrow`\(x=\dfrac{7}{2}-\dfrac{3}{4}\)

`\Rightarrow`\(x=\dfrac{11}{4}\)

Vậy, \(x=\dfrac{11}{4}\)

`4)`

\(x-\dfrac{4}{3}=\dfrac{7}{9}\)

`\Rightarrow`\(x=\dfrac{7}{9}+\dfrac{4}{3}\)

`\Rightarrow`\(x=\dfrac{19}{9}\)

Vậy, `x=`\(\dfrac{19}{9}\)

`5)`

\(x-\dfrac{5}{6}=\dfrac{7}{3}\)

`\Rightarrow`\(x=\dfrac{7}{3}+\dfrac{5}{6}\)

`\Rightarrow x =`\(\dfrac{19}{6}\)

Vậy, `x=`\(\dfrac{19}{6}\)

`6)`

\(x-\dfrac{1}{5}=\dfrac{9}{10}\)

`\Rightarrow x=`\(\dfrac{9}{10}+\dfrac{1}{5}\)

`\Rightarrow x=`\(\dfrac{11}{10}\)

Vậy, `x=`\(\dfrac{11}{10}\)

a) \(\dfrac{5}{7}\times\dfrac{5}{9}+\dfrac{4}{9}\times\dfrac{5}{7}\)

\(=\dfrac{5}{7}\times\left(\dfrac{4}{9}+\dfrac{5}{9}\right)\)

\(=\dfrac{5}{7}\times1\)

\(=\dfrac{5}{7}\)

b) \(\dfrac{1}{10}+\dfrac{5}{9}+\dfrac{4}{9}+\dfrac{9}{10}-1\)

\(=\left(\dfrac{5}{9}+\dfrac{4}{9}\right)+\left(\dfrac{1}{10}+\dfrac{9}{10}-1\right)\)

\(=1+0\)

\(=1\)

c) \(\dfrac{5}{7}\times\dfrac{5}{9}+\dfrac{4}{9}\times\dfrac{5}{7}+\dfrac{2}{7}\)

\(=\dfrac{5}{7}\times\left(\dfrac{5}{9}+\dfrac{4}{9}\right)+\dfrac{2}{7}\)

\(=\dfrac{5}{7}+\dfrac{2}{7}\)

\(=1\)

d) \(\dfrac{2}{7}+\dfrac{2}{8}+\dfrac{1}{4}+\dfrac{1}{7}+\dfrac{4}{7}\)

\(=\left(\dfrac{2}{8}+\dfrac{1}{4}\right)+\left(\dfrac{2}{7}+\dfrac{1}{7}+\dfrac{4}{7}\right)\)

\(=\left(\dfrac{1}{4}+\dfrac{1}{4}\right)+1\)

\(=\dfrac{1}{2}+1\)

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

e) \(\dfrac{4}{5}+\dfrac{3}{10}+\dfrac{2}{10}+0,7\)

\(=\dfrac{4}{5}+\dfrac{5}{10}+\dfrac{7}{10}\)

\(=\dfrac{4}{5}+\dfrac{12}{10}\)

\(=\dfrac{4}{5}+\dfrac{6}{5}\)

\(=\dfrac{10}{5}\)

\(=2\)

g) \(362\times728+326\times272\)

\(=326\times\left(728+272\right)\)

\(=326\times1000\)

\(=326000\) 

1/   Suy ra: -35 + 7x - 2x + 20 = 15

                5x - 15 = 15

                 5x = 30

                  x = 6

2/  Suy ra:  4x - 20 - 3x - 21 = -19

                   x - 41  = -19

                    x  = 22

3/   Suy ra:   8 - 4x + 3x - 15 = 14

                    -7 -x = 14

                      x = -7 -14

                      x = -21

4/    Suy ra:   7x - 63 - 30 + 5x = -6 + 11x

                      7x + 5x - 11x = -6 +63 + 30

                       x   =    87

5/    Suy ra:  -21x +35 + 14x - 28 = 28

                       -21x + 14x = 28 +28 - 35

                         -7x = 21

                             x= -3

6/     Suy ra:  20 - 5x + 7x - 14 = -2

                        2x   =   -8

                          x = -4

7/    Suy ra:   4x +15 -5x = 7

                      -x = -8

                        x = 8

 8/   Suy ra:   5x - 35 +30 -10x = 20

                      -5x - 5 = 20

                          -5x = 25

                            x = -5

9/    Suy ra:     35 - 7x + 5x - 10 = 15

                         -7x + 5x = 15 +10 - 35

                        -2x = -10

                          x = 5

Bài 1:

a) \(x.\dfrac{3}{4}=\dfrac{9}{14}\)

\(\Rightarrow x=\dfrac{9}{14}:\dfrac{3}{4}\)

\(\Rightarrow x=\dfrac{6}{7}\)

b) \(x:\dfrac{5}{9}=\dfrac{3}{10}\)

\(\Rightarrow x=\dfrac{3}{10}.\dfrac{5}{9}\)

\(\Rightarrow x=\dfrac{1}{6}\)

help me

Bài 2:

a) \(\dfrac{3}{10}+\dfrac{2}{5}:\dfrac{4}{15}=\dfrac{3}{10}+\dfrac{3}{2}=\dfrac{9}{5}\)

b) \(\dfrac{4}{7}.3+\dfrac{2}{3}.2=\dfrac{12}{7}+\dfrac{4}{3}=\dfrac{64}{21}\)

a: =16-2+91=14+91=105

b: =9*5+8*10-27=45+53=98

c: =32+65-3*8=8+65=73

d; \(=5^3-10^2=125-100=25\)

e: \(=4^2-3^2+1=8\)

f: =9*16-16*8-8+16*4

=16(9-8+4)-8

=16*5-8

=72

a) \(2^4-50:25+13\cdot7\)

\(=2^4-2+91\)

\(=16-2+91\)

\(=14+91\)

\(=105\)

b) \(3^2\cdot5+2^3\cdot10-3^4:3\)

\(=9\cdot5+8\cdot10-3^3\)

\(=45+80-27\)

\(=98\)

c) \(2^5+5\cdot13-3\cdot2^3\)

\(=32+65-3\cdot8\)

\(=32+65-24\)

\(=73\)

d) \(5^{13}:5^{10}-5^2\cdot2^2\)

\(=5^{13-10}-\left(5\cdot2\right)^2\)

\(=5^3-10^2\)

\(=125-100\)

\(=25\)

e) \(4^5:4^3-3^9:3^7+5^0\)

\(=4^{5-3}-3^{9-7}+1\)

\(=4^2-3^2+1\)

\(=16-9+1\)

\(=8\)

f) \(3^2\cdot2^4-2^3\cdot4^2-2^3\cdot5^0+4^2\cdot2^2\)

\(=3^2\cdot4^2-2^3\cdot4^2-2^3\cdot1+4^2\cdot2^2\)

\(=4^2\cdot\left(3^2-2^3+2^2\right)-2^3\)

\(=4^2\cdot\left(9-8+4\right)-8\)

\(=16\cdot5-8\)

\(=72\)

\(x\cdot\frac{22}{9}=\frac{22}{5}-\frac{11}{7}\)

\(x\cdot\frac{22}{9}=\frac{99}{35}\)

\(x=\frac{99}{35}:\frac{22}{9}\)

\(x=\frac{81}{70}\)

Vậy \(x=\frac{81}{70}\).

\(x:\frac{56}{5}=\frac{26}{5}+\frac{52}{5}\)

\(x:\frac{56}{5}=\frac{78}{5}\)

\(x=\frac{78}{5}\cdot\frac{56}{5}\)

\(x=\frac{4368}{25}\)

Vậy \(x=\frac{4368}{25}\).

\(x:\frac{19}{3}=4\)

\(x=4\cdot\frac{19}{3}\)

\(x=\frac{76}{3}\)

Vậy \(x=\frac{76}{3}\).