Complex Arithmetic/Examples/3(-1+4i) - 2(7-i)

From ProofWiki
Jump to navigation Jump to search

Example of Complex Arithmetic

$3 \paren {-1 + 4 i} - 2 \paren {7 - i} = -17 + 14 i$


Proof

\(\ds 3 \paren {-1 + 4 i} - 2 \paren {7 - i}\) \(=\) \(\ds \paren {3 \times -1 + 3 \times 4 i} - \paren {2 \times 7 - 2 \times i}\)
\(\ds \) \(=\) \(\ds \paren {-3 + 12 i} - \paren {14 - 2 i}\)
\(\ds \) \(=\) \(\ds \paren {-3 - 14} + \paren {12 - \paren {-2} } i\) Definition of Complex Subtraction
\(\ds \) \(=\) \(\ds -17 + 14 i\)

$\blacksquare$


Sources