Answer:
x = 3
Step-by-step explanation:
Data
Therefore:
From Intersecting Secants Theorem :
CD*CE = CB*CA
Replacing with data:
(x + 1)*(x + 15) = x*(x + 21)
x² + 15x + x + 15 = x² + 21x
x² + 15x + x + 15 -x² - 21x = 0
15 - 5x = 0
15 = 5x
15/5 = x
3 = x