Hai số phức \(z = a + bi,z' = a + b'i\) bằng nhau nếu:

\(a\)

\(b\)

\(i\)

\(z\)

\( - 1\)

\(2\)

\(1\)

\(\sqrt 2 \)

\(a - bi\)          

\(a + bi\) 

\(b - ai\)          

\(b + ai\)

\(\overline z  = z\)       

\(\left| {\overline z } \right| = \left| z \right|\)             

\(\left| z \right| + \left| {\overline z } \right| = 0\)

\(\left| {\overline z .z} \right| = 0\)

\(M\left( {a;a'} \right)\)

\(N\left( {b;b'} \right)\)          

\(M\left( {a;b} \right)\)

\(N\left( {b';a'} \right)\) 

\(z + z' = \left( {a + b} \right) + \left( {a' + b'} \right)i\)        

\(z - z' = \left( {a + a'} \right) - \left( {b + b'} \right)i\) 

\(z.z' = \left( {aa' - bb'} \right) + \left( {ab' + a'b} \right)i\) 

\(z.z' = \left( {aa' + bb'} \right) - \left( {ab' + a'b} \right)i\)