Ta có: \(\frac{x-3}{x+5}=\frac{5}{7}\)

\(\Rightarrow7.\left(x-3\right)=5.\left(x+5\right)\)

\(\Rightarrow7x-21=5x+25\)

\(\Rightarrow7x-5x=21+25=46\)

\(\Rightarrow2x=46\)

\(\Rightarrow x=46:2=23\)

Vậy x = 23

Ủng hộ mik nha!

\(2\left(|x-1|+x-\frac{4}{5}\right)=2x-\frac{2}{5}\)

\(TH1:x\ge1\Rightarrow|x-1|=x-1\)

\(\Rightarrow2\left(x-1+x-\frac{4}{5}\right)=2x-\frac{2}{5}\)

\(\Rightarrow2\left(2x-\frac{9}{5}\right)=2x-\frac{2}{5}\Rightarrow4x-\frac{18}{5}=2x-\frac{2}{5}\)

\(\Rightarrow4x-2x=\frac{18}{5}-\frac{2}{5}\Rightarrow2x=\frac{16}{5}\Rightarrow x=\frac{16}{5}:2=\frac{16}{10}=\frac{8}{5}\)

\(TH2:x< 1\Rightarrow|x-1|=-x+1\)

\(\Rightarrow2\left(-x+1+x-\frac{4}{5}\right)=2x-\frac{2}{5}\)

\(\Rightarrow2\left(1-\frac{4}{5}\right)=2x-\frac{2}{5}\Rightarrow2\cdot\frac{1}{5}=2x-\frac{2}{5}\)

\(\Rightarrow2x-\frac{2}{5}=\frac{2}{5}\Rightarrow2x=\frac{2}{5}+\frac{2}{5}=\frac{4}{5}\Rightarrow x=\frac{4}{5}:2=\frac{4}{10}=\frac{2}{5}\)

Do (-x)^2 = x^2 nên:

=> (2/5)^x > (2/5)^3 × (2/5)^2

=> (2/5)^x > (2/5)^5

=> x > 5 (t/ m).

Chúc bạn học tốt!!😀😀

ooooo thanks

\(\left|x\right|>5\)

\(x>5\)

vay \(x>5\)

x=rỗng