solve for xx=?(i don't know why but why i can't see the answer that other people answered me?)

Similar Triangles
Triangles ABC and ADE are similar which means their corresponding side lengths are in the same proportion.
The height of triangle ABC is 1
The height of triangle ADE is 5
The base of triangle ABC is x
The base of triangle ADE is x + 9
Therefore:
[tex]\frac{5}{1}=\frac{x+9}{x}[/tex]Cross-multiplying:
[tex]\begin{gathered} 5x=x+9 \\ \\ Subtracting\text{ x:} \\ \\ 4x=9 \\ \\ Dividing\text{ by 4:} \\ \\ x=\frac{9}{4} \end{gathered}[/tex]