# How do you multiply (5+5i)(-3-7i)?

There are at least two ways to do the multiplication. I recommend, F.O.I.L.: $- 15 - 35 i - 15 i - 35 {i}^{2} = 20 - 50 i$
${i}^{2} = - 1$ this turns $- 35 {i}^{2}$ into $+ 35$