Question

How do i multiply (6-3i)(4+9i) and write my answer in standard form?

Answer 1

@tiffanyyy31 will show you one way, i will show you another

\[(a+bi)(c+di)=(ac-bc)+(ad+bc)i\]

Answer 2

Take for example (a-bi)(a+bi)
Using the FOIL method,
Same goes for this equation
6(4)+6(9i)-3i(4)-3i(9i)
multiply and combine like terms
24+54i-12i-27i^2
Remember that i^2=-1
so now you have 24+42i-27(-1)
combine like terms to give you
51+42i
And this is in standard form. :)