a.

\(\frac{4}{7}x-\frac{2}{3}=\frac{1}{5}\)

\(\frac{4}{7}x=\frac{1}{5}+\frac{2}{3}\)

\(\frac{4}{7}x=\frac{3+10}{15}\)

\(\frac{4}{7}x=\frac{13}{15}\)

\(x=\frac{13}{15}\div\frac{4}{7}\)

\(x=\frac{13}{15}\times\frac{7}{4}\)

\(x=\frac{91}{60}\)

b.

\(\frac{2}{9}+\frac{7}{8}x=\frac{1}{3}\)

\(\frac{7}{8}x=\frac{1}{3}-\frac{2}{9}\)

\(\frac{7}{8}x=\frac{3-2}{9}\)

\(\frac{7}{8}x=\frac{1}{9}\)

\(x=\frac{1}{9}\div\frac{7}{8}\)

\(x=\frac{1}{9}\times\frac{8}{7}\)

\(x=\frac{8}{63}\)

Chúc bạn học tốt

c) pt <=> \(x-\frac{21}{5}=\frac{23}{7}< =>x=\frac{23}{7}+\frac{21}{5}=\frac{262}{35}\)

vậy x = \(\frac{262}{35}\) 

d) \(x-\frac{3}{4}=\frac{51}{8}< =>x=\frac{51}{8}+\frac{3}{4}=\frac{57}{8}\) 

vậy x = \(\frac{57}{8}\) 

e) pt <=> \(\frac{7}{8}:x=\frac{7}{2}< =>\frac{7}{8}.\frac{1}{x}=\frac{7}{2}< =>\frac{7}{8x}=\frac{7}{2}< =>56x=14< =>x=\frac{14}{56}=\frac{1}{4}\)

vậy x = \(\frac{1}{4}\)

a) pt <=> \(x+\frac{11}{4}=\frac{17}{3}< =>x=\frac{17}{3}-\frac{11}{4}=\frac{35}{12}\)

vậy x = \(\frac{35}{12}\)

b) pt <=> \(\frac{x.7}{2}=\frac{19}{4}< =>x=\frac{19.2}{4.7}=\frac{38}{28}=\frac{19}{14}\)

vậy x = \(\frac{19}{14}\) 

b) \(\frac{2}{9}+\frac{7}{8}.x=\frac{1}{3}\)

\(\frac{1}{3}-\frac{2}{9}=\frac{7}{8}.x\)

\(\frac{7}{8}.x=\frac{1}{9}\)

\(x=\frac{1}{9}:\frac{7}{8}\)

\(x=\frac{8}{63}\)

c) \(\frac{4}{5}+\frac{5}{7}:x=\frac{1}{3}\)

\(\frac{5}{7}:x=\frac{1}{3}-\frac{4}{5}\)

\(\frac{5}{7}:x=\frac{-7}{15}\)

\(x=\frac{5}{7}:\frac{-7}{15}\)

\(x=\frac{75}{-49}\)

b) \(\frac{2}{9}+\frac{7}{8}x=\frac{1}{3}\)

\(\frac{7}{8}x=\frac{1}{3}-\frac{2}{9}=\frac{1}{9}\)

\(x=\frac{1}{9}:\frac{7}{8}=\frac{8}{63}\)

c) \(\frac{4}{5}+\frac{5}{7}:x=\frac{1}{3}\)

\(\frac{5}{7}:x=\frac{1}{3}-\frac{4}{5}=-\frac{7}{15}\)

\(x=\frac{5}{7}:\left(-\frac{7}{15}\right)=-\frac{75}{49}\)

\(1,\)\(x-\frac{3}{5}=\frac{3}{35}-\frac{-7}{6}\)

        \(x-\frac{3}{5}=\frac{3}{35}+\frac{7}{6}\)

        \(x-\frac{3}{5}=\frac{263}{210}\)

                    \(x=\frac{263}{210}+\frac{3}{5}\)

                    \(x=\frac{389}{210}\)

        VẬY: \(x=\frac{389}{210}\)

\(\frac{10}{3}.x+\frac{67}{4}=\frac{53}{4}\)

\(\frac{10}{3}.x=\frac{53}{4}-\frac{67}{4}\)

\(\frac{10}{3}.x=-\frac{7}{2}\)

\(x=-\frac{7}{2}:\frac{10}{3}\)

\(x=-\frac{21}{20}\)

1. \(x=\frac{61}{42}\)

2. \(x=\frac{-36}{5}\) 

3. \(x=\frac{13}{11}\)

4. \(x=\frac{1}{12}\)

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

a) X-4,2=58,4-24,9

 X-4,2= 33,5

X= 33,5+4,2

X=37,7

b) \(\frac{4}{5}-X=\frac{1}{5}+\frac{2}{7}\)

\(\frac{4}{5}-X=\frac{17}{35}\)

\(X=\frac{4}{5}-\frac{17}{35}\)

\(X=\frac{5}{7}\)

c)\(X-140:35=270\)

\(X-4=270\)

X=274

d) 3.X + 2.X = 25

 X.(3+2) = 25

X = 25:(3+2)

X=5

a)                                                                  b) \(\frac{4}{5}-x=\frac{1}{5}+\frac{2}{7}\) 

x – 4,2 = 58,4 – 24,9                                           \(\frac{4}{5}-x=\frac{17}{35}\)

x – 4,2 = 33,5                                                                \(x=\frac{4}{5}-\frac{17}{35}\)

x           = 33,5 + 4,2                                                      \(x=\frac{11}{35}\)

x           = 37,7

c)                                                                 d) \(3\times x+2\times x=25\)

x – 140 : 35 = 270                                                \(x\times\left(3+2\right)=25\)

x       -     4    = 270                                                            \(x\times5=25\)

x                   = 270 + 4                                                            \(x=25\div5\)

x                   = 274                                                                  \(x=5\)