You can
put this solution on YOUR website!using the foil method multiply out the question the first of term a to the two terms in b, and the second term in a by the 2 terms in b.
so you get
(5)(3)+(5)(-7i)+(4i)(3)+(4i)(7i)
or
15-35i+12i+28i^2
combine like terms
28i^2-(23i)+15
(