Dividing Complex numbers

Dividing Complex numbers

Review of multiplying complex numbers

Remember i² = -1

Multiple Choice

(i)(3i)

• -3i
• -3
• 3
• 2i

Multiple Choice

(-3-i)(6-i)

• -21-7i
• -19-3i
• -15-5i
• -17-9i

Multiple Choice

(7-5i)(7+5i)

• 74
• 75
• 74-1

Find the conjugate

The conjugate of a + bi is a - bi

The conjugate of a - bi is a + bi

Multiple Choice

What is the conjugate of 2 + 3i?

• 2 - 3i

• -2 + 3i

• -2 - 3i

• 2 + 3i

Multiple Choice

What is the conjugate of -5 + 4i

• 5 + 4i

• 5 - 4i

• -5 - 4i

• -5 + 4i

Multiple Choice

What is the conjugate of 4i?

• 4i

• 4 + 4i

• 4-4i

• -4i

To divide complex numbers

Multiply the top and bottom by the conjugate of the denominator

Multiple Choice

 $\frac{5-8i}{3+2i}$  , what do you do to divide?

• Multiply the top and bottom by 3-2i

• Multiply the top and bottom by 5 + 8i

• multiply the top by 5 + 8i and the bottom by 3 - 2i

• Multiply the top and bottom by -3 - 2i

Multiple Choice

Simplify

Multiple Choice

• A
• B
• C
• D

Multiple Choice

• A
• B
• C
• D

Multiple Choice

• A
• B
• C
• D