Answer:
x=6
Explanation:
You can find the answers using similar triangles.
The leftmost side of the small triangle we shall call y. The leftmost side of the big triangle is twice this: 2y.
This tells us that the the side lengths in the big triangle are twice that of the small:
19x-28=2(6x+7)
19x-28=12x+14
7x=42
x=6