Complex Numbers and Conjugates

Rationalize the denominator and simplify the expression (5 - 4i) / (2i).

• 2 + 2.5i

• -2 + 2.5i

• -2 - 2.5i

• 2 - 2.5i

Divide the complex numbers (1 + i) by (1 - i) and express the result in standard form.

• 1

• i

• 0

• -1

What is the complex conjugate of (1+8i)/(2-4i) ?

• - 8i

• + 8i

• - 4i

• + 4i

• - 2i

Find the conjugate of the complex number: 4 - 7i

• 4 - 7i

• 4 + 7i

• 4 + 7

• 7 - 4i

Imagine you are watching a cartoon where a magical character has a power of (7 + 3i). If the villain uses a spell to conjugate this power, what will be the new power of the character?

• 7 - 3i

• -7 + 3i

• 7 + 3i

• -7 - 3i

Find the conjugate of the complex number 9 - 3i.

• 9 - 3i

• 3 - 9i

• 9 + 3i

• 9 + 3

What is the conjugate of
7-2i? 

• 7+2i

• 7-2i

• 2-7i

• 2+7i

• 7 - 2i

• -7 - 2i

• -7 + 2i

• 7 + 2i

What is the complex conjugate of 4-3i?

• A. 1/(4-3i)

• B. 1/(4+3i)

• C. -4 + 3i

• D. 4 + 3i

Answer explanation

A conjugate of a complex number will have the same terms and an opposite +/- between them:

x = a + bi and it's conjugate is x = a - bi

Find the conjugate of the complex number 4 + 7i.

• 4 + 7i

• 7 - 4i

• 7 + 4i

• 4 - 7i