Answer:
DE = 3 units
Explanation:
The image is attached.
There are 2 secant lines in the circle. We can use secant theorem to solve this easily.
It states that "if 2 secants are drawn to a circle from an outside point, then product of 1 secant and its "outside" part is equal to product of other secant and its "outside" part.
From the figure, we can say:
AX * BX = EX * DX
We let the length to find , DE, be "x".
Thus, we can write:
![AX * BX = EX * DX\\(7+2)(2)=(x+3)(3)](https://img.qammunity.org/2021/formulas/mathematics/college/2nn1smqnggx786kocac4f1tfqle425swzn.png)
Now, we solve this for x:
![(7+2)(2)=(x+3)(3)\\(9)(2)=(3)(x+3)\\18=3x+9\\3x=18-9\\3x=9\\x=3](https://img.qammunity.org/2021/formulas/mathematics/college/ctgk9z65zmunw9a0g4kpsgbhmmn7enxsit.png)
Thus,
DE = 3 units