Question

Question 20 of 41 Which of the following is the product of the complex numbers below? (7+41) (2-31) O A. 26-137 B. 2+297 C. 2-13; O D. 26+29;

Answer 1

The given multiplication is:

$(7+4i)(2-3i)$

First, apply the distributive property:

$\begin{gathered} =7\cdot2-7\cdot3i+4i\cdot2-4i\cdot3i \\ =14-21i+8i-12i^2 \\ =14-13i-12i^2 \end{gathered}$

i^2 is equal to -1, then:

$\begin{gathered} =14-13i-12(-1) \\ =14-13i+12 \\ =26-13i \end{gathered}$

The answer is A. 26-13i