What is the value of x?
O
O
O
O
2 units
3 units
5 units
8 units
A
X
D

D. 8 units

Step-by-step explanation:

Triangle ABD is a 30/60/90 degree triangle.

If one side is 10 and another is 8, that makes the common triangle proportions of 3, 4. 5 units. The third side would be 6 units.

"image"

step-by-step explanation:

in most of these problems, the notation is that the point with a "prime" is the image of the point without. that is, b' is the image of b.

here, there is no dilation or reflection. there is simply translation (with no direction shown). which figure you call the "preimage" and which one you call the "image" is up to you. as a matter of convention, the naming is as described above.