\(;\frac{2}{3}.\frac{5}{x}+\frac{5}{7}=\frac{10}{21}+\frac{10}{9}\)
\(;\frac{10}{3x}+\frac{5}{7}=\frac{100}{63}\)
\(;\frac{10}{3x}=\frac{100}{63}-\frac{5}{7}=\frac{55}{63}\)
\(;3x=10:\frac{55}{63}=\frac{126}{11}\)
\(;x=\frac{126}{11}:3=\frac{42}{11}\)
\(\frac{2}{3}:\frac{x}{5}+\frac{5}{7}=\frac{2}{7}:\frac{3}{5}+\frac{10}{9}\)
→ \(\frac{2}{3}:\frac{x}{5}+\frac{5}{7}=\frac{10}{21}+\frac{10}{9}=\frac{100}{63}\)
→ \(\frac{2}{3}:\frac{x}{5}=\frac{100}{63}-\frac{5}{7}\)
→ \(\frac{2}{3}:\frac{x}{5}=\frac{55}{63}\)
→ \(\frac{x}{5}=\frac{2}{3}:\frac{55}{63}\)
→ \(\frac{x}{5}=\frac{42}{55}\)
→ \(x:5=\frac{42}{55}\)
→ x = \(\frac{42}{55}\) . 5
→ x = \(\frac{42}{11}\) = 3,8
→ x : 5 = \(\frac{42}{55}\)
→ \(\frac{x}{5}=\frac{42}{55}\)