how do i solve this step by step? i dont know how to set up this equation

Answer:
23
Step-by-step explanation:
The markings show that the vertical line and the hypotenuse are bisected. That means that the common ratio is 1/2.
(x - 8) / 30 = 1/2 Cross multiply
2(x - 8) = 30 Divide both sides by 2
x - 8 = 30/2
x - 8 = 15 Add 8 to both sides
x-8+8 =15+8
x = 23