Answer
$40+13i$
Work Step by Step
Using $(a+b)(c+d)=ac+ad+bc+bd$, or the product of 2 binomials, and the properties of radicals, the given expression, $
(5-6i)(2+5i)
,$ simplifies to
\begin{array}{l}\require{cancel}
5(2)+5(5i)-6i(2)-6i(5i)
\\\\=
10+25i-12i-30i^2
\\\\=
10+13i-30i^2
\\\\=
10+13i-30(-1)
\\\\=
10+13i+30
\\\\=
40+13i
.\end{array}