Practice Multiplying and Dividing Complex Numbers

 

Solve the following problems.  Answers are to be in simplest a+bi form.
  You should be able to solve the problems with and without
using your graphing calculator.

1.

 

      Multiply:   (3+5i)(3-5i)

Choose:

9-25i
 25
34

 

 

2.

     Multiply:  (8+9i)(7-3i)

Choose:

15-12i
 29-39i
83+39i

 

 

3.

Multiply:  (4-3i)(3-4i)

Choose:

25
 -25i
12-12i

 

 

4.

Simplify:  (2+5i)2

Choose:

21+20i
 -21+20i
29+20i

 

 

5.

Simplify:  8+i(8-i)

Choose:

7+8i
 8+8i
9+8i

 

 

6.

     Simplify:

Choose:

5-2i
 3+2i
15+10i

 

 

7.

      Simplify:   

Choose:

35/37 + (12/37)i
 35 + 12i
35/36 + (12/36)i

 

 

8.

     Simplify: 

Choose:

5+3i
 -5-3i
5-3i

 

 

9.

    Simplify: 

Choose:

2/15 + i/15
 2/15 - i/15
1/45 + i/15

 

 

10.

What is the multiplicative inverse of

 

Choose:

2/(1+i)
 (1/2)-(1/2)i
(1+i)/2

 

 


Roberts