On the left hand side express as a single fraction, which involves multiplying the denominators, which gives denominator (x2 - y2), unfortunately not quite the same as a denominator appearing on the right-hand side - and I wonder whether you have transcribed it properly, whether it is not really 12i/(y2 + x2). If it is that, you can combine those two bits into (something)/(x4 - y4). Whether it's that or really ...+ 12i/y2 +... still combine into one fraction. In the end express the whole thing with a single denominator. Numerator = 0 gives you solutions but watch out whether enumerator and denominator have common factor which=0 is not a solution of problem.
You being stuck suggests you probably need to revise adding/subtracting fractions, you may need to revise how to deal with expressions with complex numbers - here nothing needed except work like with real numbers but just whenever you get i2 it becomes -1.
I haven't done it and don't know whether any significant simplifications come up; it is some work but a quite routine problem.