Question 90415
*[Tex \LARGE (9-5i)(1+3i)] Start with the given expression


*[Tex \LARGE (9)(1)+(9)(3i)+(1)(-5i)+(-5i)(3i)] Foil


*[Tex \LARGE 9+27i-5i-15i^2] Multiply


*[Tex \LARGE 9+27i-5i-15(-1)] Evaluate {{{i^2}}} to get -1


*[Tex \LARGE 9+27i-5i+15] Multiply


*[Tex \LARGE 24+22i] Combine like terms. So it is now in {{{a+bi}}} form where {{{a=24}}} and {{{b=22}}}