Answer
$9k^2-30km+25m^2$
Work Step by Step
$\bf{\text{Solution Outline:}}$
To simplify the given expression, $
(3k-5m)^2
,$ use the special product on squaring binomials.
$\bf{\text{Solution Details:}}$
Using the square of a binomial which is given by $(a+b)^2=a^2+2ab+b^2$ or by $(a-b)^2=a^2-2ab+b^2,$ the expression above is equivalent to
\begin{array}{l}\require{cancel}
(3k)^2-2(3k)(5m)+(5m)^2
\\\\=
9k^2-30km+25m^2
.\end{array}
