Question

If (x+yi)+(2(x+yi)+3i)=9, what is (x+yi)?

Answer 1

X + yi + 2x + 2yi + 3i = 9    this first step is just distributing the 2 

3x + 3yi = -3i + 9        this step is adding like terms 

x+ yi = 3 - i             this step is dividing by 3 to all terms... Lowest common factor
                                 then subtracting 3i to the right side of the equation  

so x =3 and y= -1
if that the full question?