Answer
$-3x^2-5x+1$
Work Step by Step
Since the grouping symbol is preceded by a negative sign, then the sign of each term inside the grouping symbol alters once the grouping symbol is removed. Hence, the given expression, $
-(3x^2+5x-1)
$, is equivalent to
\begin{array}{l}\require{cancel}
-3x^2-5x+1
.\end{array}