How do I do this? It's a modulus question.

1)
||x|-4|= |x-1|
1st step = separate the equation into 2 possible equations
2nd step = solve the equations
|x|-4= x-1
x= -3/2
Or
|x|-4= - (x-1)
X= 5/2

2)

Do the same
X= -5/2
X= 7/2

Aand b is what i think

14 is the best answer can i get brainliest?