i mean

how IF X=[1,4] & A=[2,4] then A' =3. A` =

Gives answer[1,3]

how IF A[1,2] & B0,2) then A(Intersection Sign)B=

Gives answer[1,2)

Also have another question

1. If the area of a triangle is 16, formed by the points Z, Z+iZ and iZ in a complex plane then |Z|=_____

Gives 4(Under-root-->2) how?