Question 1194520
z1=2-2i  and z2=3i and z3=  -3+1  now 
c)  z1*z3 =  6i-6i^2  (i^2=-1  as i = {{{sqrt(-1)}}} 
  so  it will become 
  6i+6= 6+6i  we get
Now I believe you can do d 

for e 
angle between z1 and z2 
z1(2, -2)  and z2 (0,3)  on a graph
take origin as a reference point now draw on a graph 
  
now y= 3 has 0 slope so angle 0 but 2,-2 has -pie/4  as angle= tan^-1 (-2/2)
now angle between z1 and z2 is z1-z2 is angle between them so -pie/4 -0  =-pie/4 
this is the simplest method.