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Imaginary and Complex Numbers

Total questions: 27

Worksheet time: 41mins

Name
Class
Date
1.

What is an imaginary number?

a)

A number that cannot be used in mathematical calculations

b)

A complex number that can be written as a real number multiplied by the imaginary unit i.

c)

A number that doesn't exist in the real world

d)

A number with no value

2.

What is a complex number?

a)

A number that can be expressed in the form a + bi, where a and b are real numbers, and i is the imaginary unit.

b)

A number that can only be expressed in the form a - bi

c)

A number that has no real part

d)

A number that can only be expressed in the form a + bi

3.

Simplify the expression: √(-16)

a)

4i

b)

16

c)

-4

d)

0

4.

What is the value of i^2?

a)

1

b)

2

c)

0

d)

-1

5.

Add (3 + 2i) + (4 - 5i) and write the answer in a + bi form.

a)

9 - 2i

b)

2 - 3i

c)

7 - 3i

d)

5 + 7i

6.

Subtract (5 - 3i) - (2 + 4i) and write the answer in a + bi form.

a)

2 - 7i

b)

4 - 5i

c)

3 - 7i

d)

8 - 1i

7.

Perform the operation (3 + 2i) * (4 - 5i) and write the answer in a + bi form.

a)

15 + 3i

b)

20 - 10i

c)

22 - 7i

d)

12 - 7i

8.

If z = 2 + 3i and w = 4 - 2i, find z + w and write the answer in a + bi form.

a)

6 + i

b)

2 - 5i

c)

10 + 3i

d)

8 - i

9.

If a = 1 + 2i and b = 3 - 4i, find a + b and write the answer in a + bi form.

a)

4 - 2i

b)

2 - 6i

c)

4 - 6i

d)

2 - 2i

10.

What is the value of i^3?

a)

1

b)

i

c)

-1

d)

-i

11.

What is the imaginary part of the complex number: 5 - 6i

a)

5

b)

-6i

12.

Find the real part of the complex number: 7 + 8i

a)

7

b)

8

c)

15

d)

1

13.

What is the square root of -1?

a)

1

b)

i

c)

-1

d)

0

14.

If z = 3 + 4i and w = 1 - 2i, find z + w and write the answer in a + bi form.

a)

4 + 2i

b)

2 + 2i

c)

4 - 2i

d)

2 - 2i

15.

What is the real part of a complex number?

a)

The 'a' in the expression a + bi

b)

The 'b' in the expression a + bi

c)

The 'i' in the expression a + bi

d)

Both 'a' and 'b' in the expression a + bi

16.
Multiply:
(2-5i)(2+5i)
a)
29
b)
4 - 25i
c)
25 - 10i
d)
-21
17.
i79
a)
i
b)
1
c)
-1
d)
-i
18.
(2i)(3i)
a)
5i
b)
-5
c)
6i2
d)
-6
19.
(3i)(-2+4i)
a)
-6+12i
b)
-12-6i
c)
-2+7i
d)
12+6i
20.
i13
a)
-1
b)
1
c)
i
d)
-i
21.
a)

7

b)

-7

c)

7i

d)

-7i

22.
Simplify:
3√-81
a)
-27
b)
3i√3
c)
27i
d)
9i
23.

Fully simplify. (6−7)(−3)\left(6\sqrt{-7}\right)\left(\sqrt{-3}\right)  

a)

−6i21-6i\sqrt{21}  

b)

−621-6\sqrt{21}  

c)

6216\sqrt{21}  

d)

6i216i\sqrt{21}  

24.

Write −200\sqrt{-200} in simplest radical form. 

a)

5−85\sqrt{-8}  

b)

5i85i\sqrt{8}  

c)

10i210i\sqrt{2}  

d)

10−210\sqrt{-2}  

25.

Write −10\sqrt{-10} in simplest radical form.  

a)

−i10-i\sqrt{10}  

b)

i10i\sqrt{10}  

c)

−52-\sqrt{5}\sqrt{2}  

d)

52−1\sqrt{5}\sqrt{2}\sqrt{-1}  

26.

−100+−9+9−−16-\sqrt{100}+\sqrt{-9}+\sqrt{9}-\sqrt{-16}  

a)

13 +7i

b)

-7 - 7i

c)

13 - i

d)

-7 - i

27.

144−−90+16+−10\sqrt{144}-\sqrt{-90}+\sqrt{16}+\sqrt{-10}  

a)

16−2i1016-2i\sqrt{10}  

b)

16+4i1016+4i\sqrt{10}  

c)

16+3i1016+3i\sqrt{10}  

d)

12−2i1012-2i\sqrt{10}