If you are implying that the triangles are similar, then the short and long legs are in proportion:

Solving for x, you have

Answer: 3
Step-by-step explanation:
11- 2x2x2 since its 2 to the power of 3 which will give you 8 and than you basically just subtract 11- 8=3
Answer:
x = 10
Step-by-step explanation:
We need to isolate X.
3x - 7 = x + 13
subtract 13
3x - 7 - 13 = x
combine like terms
3x - 20 = x
subtract 3x
- 20 = x - 3x
Combine like terms
- 20 = - 2x
Divide by -2
10 = x