Answer:
x=5
Explanation:
We can use proportions to solve this problem. Put the side of the small triangle over the side of the large triangle.
9 15
------ = ----------
2x-1 3x
Using cross products
9*3x = 15(2x-1)
27x = 30x-15
Subtract 30x from each side
27x-30x = 30x-30x -15
-3x = -15
Divide by -3
-3x/-3 = -15x/-3
x = 5