Question

which of the following is equivalent to the expression (i+5)(3+4i)

Answer 1

the options are:

A) 11+23i
B) 15+19i
C) 19+23i
D) 23i

Answer 2

Well, the first thing you need to remember is that \[i^{2} = - 1\]
Then you just multiply out the equation like you normally would.
\[(i+5)(3+4i)\]
\[3i + 4i^{2} + 15 + 20i\]
substituting in the i^2
\[3i - 4 + 15 + 20i\]
Then combine like terms
\[11 + 23i\]

Answer 3

Thank you so much!