Question

(3-5i)(2+9i)+(7+2i)(7-2i)

Answer 1

$i^{2} = -1$

-----------------------------------------

$(3-5i)(2+9i)+(7+2i)(7-2i) = \\ \\ = 6 + 27i - 10i - 45i^{2} + 49 - 14i + 14i - 4i^{2} = \\ \\ =55 + 17i + 45 + 4 = \boxed{104 + 17i}$