Respuesta :

Answer:

x = 7

Step-by-step explanation:

<ACF = 90° (since AB is the diameter and it is perpendicular to EF)

But <ACF = 2(7x-4)

So

2(7x-4) = 90

14x-8 = 90

14x = 90+8

14x = 98

Dividing both sides by 14

x = 7