Answer
$-\dfrac{5}{x-4}$
Work Step by Step
Adding the numerators and copying the denominator, the given expression, $
\dfrac{3-2x}{x^2-6x+8}+\dfrac{7-3x}{x^2-6x+8}
,$ simplifies to
\begin{array}{l}\require{cancel}
\dfrac{3-2x+7-3x}{x^2-6x+8}
\\\\=
\dfrac{10-5x}{x^2-6x+8}
\\\\=
\dfrac{5(2-x)}{(x-2)(x-4)}
\\\\=
\dfrac{-5(x-2)}{(x-2)(x-4)}
\\\\=
\dfrac{-5(\cancel{x-2})}{(\cancel{x-2})(x-4)}
\\\\=
-\dfrac{5}{x-4}
.\end{array}