C3_W3_Bayesian inference and MAP_Query

Someone kindly help me understand how P(X=7H3T) = 7!3!/11! ?

Okay I found out that B(8,4) equals to 7!3!/11! as per the formula for Beta distribution.
But if someone can breakdown the steps which led to getting pX(7H3T) ~ B(8,4) it will help.

I saw the video provided in the link in the reading material (by Louis Serrano) on Beta distribution. But still it’s not clear how exactly we found that pX(7H3T) ~ B(8,4)
I suspect that it may be out of current scope of my understanding & this course’s syllabus.

Thank you.