The teacher will be very surprised to see your correct solution 😉
(3/10)*x+(3/100)*y = (3/25)*(x+y)
3/10x+3/100y = (3/25)*(x+y)
3/10x+3/100y = 3/25x+y
3*x/10 + 3*y/100 = 3/25x+y
3*x/10 + 3*y/100 = 3*x/25 + 3*y/25
x = 9*y/100 / (9/50)
sum
re(y) I*im(y) ----- + ------- 2 2
=
re(y) I*im(y) ----- + ------- 2 2
product
re(y) I*im(y) ----- + ------- 2 2
=
re(y) I*im(y) ----- + ------- 2 2
re(y)/2 + i*im(y)/2