Problem : 
Express 
 using the imaginary unit ı.
 = 5ı.
 
Problem : 
Is 3 a complex number?
Yes.  In standard form, it is written 
3 + 0ı.  Every real number is a 
complex number in which the imaginary part equals zero.
 
Problem : 
Rewrite the complex number 
 +3ı4 in standard form z = a + bı and find a and b.
 +3ı4 = 6ı +3 = 3 + 6ı.  
a = 3, and 
b = 6.
 
Problem : 
What is ı618?
ı618 = (ı4)154ƒı2 = - 1.
 
Problem : 
When the complex number z = - 2 + 3ı is plotted in the complex plane, 
in which quadrant is it?
Quadrant II.