Here's the question you clicked on:
Envii
1/x = 5/x-4
\[\frac{ 1 }{ x }=\frac{ 5 }{ x-4 } \rightarrow 1(x-4)=5x \]\[x-4=5x \rightarrow x-5x=4 \]\[-4x=4 \rightarrow \frac{ -4x }{ -4 }=\frac{ 4 }{ -4 } \rightarrow x=-1\]
Let me know if you understand it