∣z−1∣≤1 ⇒∣(x−1)+iy∣≤1
⇒(x−1)2+y2≤1
⇒(x−1)2+y2≤1
Also ∣z−5∣≤∣z−5i∣
(x−5)2+y2≤x2+(y−5)2
−10x≤−10y ⇒x≥y Solving (1) and (2)
⇒(x−1)2+x2=1
⇒2x2−2x=0
⇒x(x−1)=0
⇒x=0 or x=1
y=0 or y=1

Given x,y∈I
Points (0,0),(1,0),(2,0),(1,1),(1,−1) to find ∣z1∣2+∣z2∣2+∣z3∣2+∣z4∣2+∣z5∣2
=0+1+4+2+2=9