Complex Numbers: Multiplication
Worked Solution:
( 9 + j ) ( –7 + 7 j )
= 9 ( –7 + 7 j) + j( –7 + 7 j)
= –63 + 63 j – 7 j + 7 j2 but j2 = –1:
= –63 + 56 j – 7
= –70 + 56 j
AS Further Pure Mathematics (MEI Structured Mathematics FP1) Third Edition (2004) pages 46-50