Answer:
7
Step-by-step explanation:
Because these two triangles share an angle and their corresponding sides are parallel, they are similar.
So, we can set up a proportion relating corresponding sides:
10 / (10 + 8) = (3x - 6) / (3x - 6 + 12)
10/18 = (3x - 6) / (3x + 6)
Cross-multiply:
18 * (3x - 6) = 10 * (3x + 6)
54x - 108 = 30x + 60
24x = 168
x = 168/24 = 7
The answer is 7.
<em>~ an aesthetics lover</em>
