Looking at the graph
we have that
z1=(4,6i) -------> 4+6i
z2=(-5,2i) -----> -5+2i
so
Part a
Conjugate of z2
we know that
z2=-5+2i
the conjugate of z2 is -5-2i
to find out the conjugate change the sign of the imaginary part
(-5,-2i)
Part B
Find out z2-z1
z1=(4,6i)
z2=(-5,2i)
so
z2-z1=(-5-4,2i-6i)
z2-z1=(-9,-4i)
to find out the coordinate of the real axis, subtract the coordinates of the real axis and to find out the coordinate of the imaginary part, subtract the coordinates of the imaginary parts