Answer:
x = 6
Step-by-step explanation:
From the given picture,
ΔABC and ΔADE are the similar triangles.
By the property of similar triangles,
Corresponding sides of the similar triangles are proportional.
[tex]\frac{AB}{AD}=\frac{AC}{AE}[/tex]
[tex]\frac{x+18}{x}=\frac{28}{(28-21)}[/tex]
7(x + 18) = 28x
7x + 7×18 = 28x
28x - 7x = 126
21x = 126
x = [tex]\frac{126}{21}[/tex]
x = 6
