Question

Multiply the following complex numbers:

(5+3i)(4+ 2i)
A. 14-22i
O B. 14+ 22i
O C. 26 - 22i
O D. 26 + 22i

Answer 1

B, or 14 + 22i.

Explanation:

When multiplying complex numbers, use the FOIL method.

Therefore:

(5 + 3i)(4 + 2i)

FOIL the equation:

5×4 + 5 × 2i + 3i × 4 + 3i × 2i

Simplify. Remember that i² = -1.

20 + 10i + 12i -6

Combine like terms:

14 + 22i

Therefore, the solution is B, or 14 + 22i.