Which of the following shows an expression equivalent to the product of two complex numbers, 5i⋅4i ?

Answer 1

To find an expression equivalent to the product of the two complex numbers \( 5i \) and \( 4i \), we multiply them together:

\[ 5i \cdot 4i = (5 \cdot 4) \cdot (i \cdot i) = 20 \cdot i^2 \]

Recall that \( i^2 = -1 \). Thus,

\[ 20 \cdot i^2 = 20 \cdot (-1) = -20 \]

So, the product of \( 5i \) and \( 4i \) is:

\[ \boxed{-20} \]

This is the equivalent expression for the product of \( 5i \) and \( 4i \).