\(\frac{ }{ }\)

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

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

\(\Rightarrow\frac{1}{2}x=\frac{-1}{5}\)

\(\Rightarrow x=\frac{-1}{5}:\frac{1}{2}=\frac{-1}{5}\cdot\frac{2}{1}=\frac{-2}{5}\)

\(\Leftrightarrow x=\frac{-2}{5}\)

\(2)3\frac{1}{5}-2\frac{1}{3}x=-1\frac{3}{5}+1\frac{7}{10}\)

\(\Rightarrow\frac{16}{5}-\frac{7}{3}x=-\frac{8}{5}+\frac{17}{10}\)

\(\Rightarrow\frac{7}{3}x=\frac{16}{5}-\frac{-8}{5}+\frac{17}{10}\)

\(\Rightarrow\frac{7}{3}x=\frac{16}{5}+\frac{8}{5}+\frac{17}{10}\)

\(\Rightarrow\frac{7}{3}x=\frac{24}{5}+\frac{17}{10}\)

\(\Rightarrow\frac{7}{3}x=\frac{48}{10}+\frac{17}{10}\)

Đến đây tìm được rồi nhé

3,4, áp dụng bài 1,2 rồi làm :v

1. 1/2x - 3/5 = -4/5

=> 1/2x = -4/5 + 3/5

=> 1/2x = -1/5

=> x = -1/5 : 1/2

=> x = -2/5

i don't know i mới học lớp 5

bn eie mik lớp 6 nha bn

CACS BN GIÚP MIK TRẢ LỜI TRONG TỐI NAY ĐC K

a)

\(\begin{array}{l}x.\frac{{14}}{{27}} = \frac{{ - 7}}{9}\\x = \frac{{ - 7}}{9}:\frac{{14}}{{27}}\\x = \frac{{ - 7}}{9}.\frac{{27}}{{14}}\\x = \frac{{ - 3}}{2}\end{array}\)                

Vậy \(x = \frac{{ - 3}}{2}\).

b)

\(\begin{array}{l}\left( {\frac{{ - 5}}{9}} \right):x = \frac{2}{3}\\x = \left( {\frac{{ - 5}}{9}} \right):\frac{2}{3}\\x = \left( {\frac{{ - 5}}{9}} \right).\frac{3}{2}\\x = \frac{{ - 5}}{6}\end{array}\)

Vậy \(x = \frac{{ - 5}}{6}\).

c)

\(\begin{array}{l}\frac{2}{5}:x = \frac{1}{{16}}:0,125\\\frac{2}{5}:x = \frac{1}{{16}}:\frac{1}{8}\\\frac{2}{5}:x = \frac{1}{{16}}.8\\\frac{2}{5}:x = \frac{1}{2}\\x = \frac{2}{5}:\frac{1}{2}\\x = \frac{2}{5}.2\\x = \frac{4}{5}\end{array}\)      

Vậy \(x = \frac{4}{5}\)

d)

\(\begin{array}{l} - \frac{5}{{12}}x = \frac{2}{3} - \frac{1}{2}\\ - \frac{5}{{12}}x = \frac{4}{6} - \frac{3}{6}\\ - \frac{5}{{12}}x = \frac{1}{6}\\x = \frac{1}{6}:\left( { - \frac{5}{{12}}} \right)\\x = \frac{1}{6}.\frac{{ - 12}}{5}\\x = \frac{{ - 2}}{5}\end{array}\)

Vậy \(x = \frac{{ - 2}}{5}\).

Chú ý: Khi trình bày lời giải bài tìm x, sau khi tính xong, ta phải kết luận.

7/4.x+3/2=-4/5

7/4.x=-4/5-3/2

7/4.x=-23/10

x=-23/10:7/4

x=-46/35

vậy x=-46/35

1/4+3/4.x=3/4

1.x=3/4

x=3/4:1

x=3/4

vậy x=3/4

x.(1/4+1/5)-(1/7+1/8)=0

x.9/20-15/56=0

x.51/280=0

x=0:51/280

x=0

vậy x=0

3/35-(3/5+x)=2/7

(3/5+x)=3/35-2/7

(3/35+x)=-1/5

x=-1/5-3/5

x=-4/5

vậy x=-4/5

\(a,1\frac{3}{4}.x+1\frac{1}{2}=\frac{4}{5}\)

\(\frac{7}{4}.x=\frac{4}{5}-\frac{3}{2}\)

\(\frac{7}{4}.x=\frac{-7}{10}\)

\(x=\frac{-7}{10}:\frac{7}{4}\)

\(x=\frac{-2}{5}\)

\(b,\frac{1}{4}+\frac{3}{4}.x=\frac{3}{4}\)

\(\frac{3}{4}.x=\frac{3}{4}-\frac{1}{4}\)

\(\frac{3}{4}.x=\frac{1}{2}\)

\(x=\frac{1}{2}:\frac{3}{4}\)

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

\(c,x.\left(\frac{1}{4}+\frac{1}{5}\right)-\left(\frac{1}{7}+\frac{1}{8}\right)=0\)

\(x.\frac{9}{20}-\frac{15}{56}=0\)

\(x.\frac{9}{20}=\frac{15}{56}\)

\(x=\frac{15}{56}:\frac{9}{20}\)

\(x=\frac{25}{42}\)

\(d,\frac{3}{35}-\left(\frac{3}{5}+x\right)=\frac{2}{7}\)

\(\frac{3}{5}+x=\frac{3}{35}-\frac{2}{7}\)

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

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

\(x=\frac{-4}{5}\)

Học tốt

câu c mình sai 

x.(1/4+1/5)-(1/7+1/8)=0

x.9/20-15/56=0

x.9/20=0+15/56

x.9/20=15/56

x=15/56:9/20

x=25/42

vậy x=25/42

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

\(\Leftrightarrow\left(x+1\right)\left(x+2\right)=\left(x+3\right)\left(x+5\right)\)

\(\Leftrightarrow\left(x+1\right)x+\left(x+1\right).2=\left(x+3\right)x+\left(x+3\right).5\)

\(\Leftrightarrow x^2+x+2x+2=x^2+3x+5x+15\)

\(\Leftrightarrow x^2+3x+2=x^2+8x+15\)

\(\Leftrightarrow x^2+3x-x^2-8x=15-2\)

\(\Leftrightarrow-5x=13\)

\(\Leftrightarrow x=\frac{-13}{5}\)

Vậy ...

Cảm ơn bn nha 

dễ mà bạn tự làm đi động não lên

x=3/7 nha ban !!! K TUI NHA

X=3/7:5/7-3/11:5/11+3/13:5/13

+

1/2:5/4-1/3+1/4:5/6

=3/5-3/5+3/5 + 2/5-1/3+3/10

=3/5 +  11/10

=17/10

a)

\(\begin{array}{l}x:{\left( {\frac{{ - 1}}{2}} \right)^3} =  - \frac{1}{2}\\x =  - \frac{1}{2}.{\left( {\frac{{ - 1}}{2}} \right)^3}\\x = {\left( {\frac{{ - 1}}{2}} \right)^4}\\x = \frac{1}{{16}}\end{array}\)              

Vậy \(x = \frac{1}{{16}}\).

 b)

\(\begin{array}{l}x.{\left( {\frac{3}{5}} \right)^7} = {\left( {\frac{3}{5}} \right)^9}\\x = {\left( {\frac{3}{5}} \right)^9}:{\left( {\frac{3}{5}} \right)^7}\\x = {\left( {\frac{3}{5}} \right)^2}\\x = \frac{9}{{25}}\end{array}\)

Vậy \(x = \frac{9}{{25}}\).

c)

\(\begin{array}{l}{\left( {\frac{{ - 2}}{3}} \right)^{11}}:x = {\left( {\frac{{ - 2}}{3}} \right)^9}\\x = {\left( {\frac{{ - 2}}{3}} \right)^{11}}:{\left( {\frac{{ - 2}}{3}} \right)^9}\\x = {\left( {\frac{{ - 2}}{3}} \right)^2}\\x = \frac{4}{9}.\end{array}\)         

Vậy \(x = \frac{4}{9}\).

d)

\(\begin{array}{l}x.{\left( {0,25} \right)^6} = {\left( {\frac{1}{4}} \right)^8}\\x.{\left( {\frac{1}{4}} \right)^6} = {\left( {\frac{1}{4}} \right)^8}\\x = {\left( {\frac{1}{4}} \right)^8}:{\left( {\frac{1}{4}} \right)^6}\\x = {\left( {\frac{1}{4}} \right)^2}\\x = \frac{1}{{16}}\end{array}\)

Vậy \(x = \frac{1}{{16}}\).

 a) \(1\frac{2}{7} = 1 + \frac{2}{7} = \frac{9}{2}\)

\(\begin{array}{l}x:1\frac{2}{7} =  - 3,5\\x:\frac{9}{7} =  - \frac{7}{2}\\x =  - \frac{7}{2}.\frac{9}{7}\\x =  - \frac{9}{2}\end{array}\)

b) \(0,4.x - \frac{1}{5}.x = \frac{3}{4}\)

\(\begin{array}{l}\frac{2}{5}.x - \frac{1}{5}.x = \frac{3}{4}\\\left( {\frac{2}{5} - \frac{1}{5}} \right).x = \frac{3}{4}\\\frac{1}{5}.x = \frac{3}{4}\\x = \frac{3}{4}:\frac{1}{5}\\x = \frac{3}{4}.5\\x = \frac{{15}}{4}\end{array}\)

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