Answer
$(7x-8)^2\left( 121-56x \right)$
Work Step by Step
Factoring the $GCF=
(7x-8)^2
,$ the given expression, $
(5-2x)(3)(7x-8)^2(7)+(7x-8)^3(-2)
,$ is equivalent to
\begin{array}{l}\require{cancel}
(7x-8)^2\left( \dfrac{(5-2x)(3)(7x-8)^2(7)}{(7x-8)^2}+\dfrac{(7x-8)^3(-2)}{(7x-8)^2} \right)
\\\\=
(7x-8)^2\left( (5-2x)(3)(7)+(7x-8)(-2) \right)
\\\\=
(7x-8)^2\left( 105-42x-14x+16 \right)
\\\\=
(7x-8)^2\left( 121-56x \right)
.\end{array}
