Further maths help needed!

(A+bi)(2+i)=a-3i

Can someone help me solve it, as I try to do 2 simultaneous equations but I can’t get an answer that works for both equation since I keep getting the simultaneous equations a+2b=3, and the is a-b=0

Original post by Juliakinga

(A+bi)(2+i)=a-3i

Can someone help me solve it, as I try to do 2 simultaneous equations but I can’t get an answer that works for both equation since I keep getting the simultaneous equations a+2b=3, and the is a-b=0

They should be

a-b = 0

a+2b = -3

Reply 2

Juliakinga

OP

10

Original post by RDKGames

They should be

a-b = 0

a+2b = -3

Thank you, but when you substitute what you got for a or b into the first equation, a=b, but if you substitute it into the second equation you get a different answer which doesn’t work for the first equatjkn

Original post by Juliakinga

Thank you, but when you substitute what you got for a or b into the first equation, a=b, but if you substitute it into the second equation you get a different answer which doesn’t work for the first equatjkn