Answer
$2x^2-5x+10$
Work Step by Step
Removing the grouping symbols and then combining like terms, the given expression, $
(3x^2-8x+1)-(x^2-3x-9)
,$ simplifies to
\begin{array}{l}\require{cancel}
3x^2-8x+1-x^2+3x+9
\\\\=
(3x^2-x^2)+(-8x+3x)+(1+9)
\\\\=
2x^2-5x+10
.\end{array}
