← Algebra

How to solve

Multiply like binomials, then replace i² with −1 and combine.

Steps

  1. Expand (a + bi)(c + di) with FOIL.
  2. Replace i² with −1.
  3. Combine into real + imaginary form.

Example

(2 + i)(3 − 2i)

  1. 6 − 4i + 3i − 2i².
  2. −2i² = +2, so real part 6 + 2 = 8; imaginary −4i + 3i = −i.

Answer: 8-1i

How to type answers

  • Write it like 8-1i or 8-i
Loading drills…