Answer
$-a+58$
Work Step by Step
Using the Distributive Property and then combining like terms, the given expression, $
-4(a+2)+6(a+8)-3(a-6)
,$ simplifies to
\begin{array}{l}\require{cancel}
-4a-8+6a+48-3a+18
\\\\=
(-4a+6a-3a)+(-8+48+18)
\\\\=
-a+58
.\end{array}