Answer
$-33$
Work Step by Step
We will evaluate the expression by first simplifying the expression and then substituting $n=3$ into the resultant expression:
$2(n^{2}-3n-1)-(n^{2}+n+4)-3(2n-1)$
=$2n^{2}-6n-2-n^{2}-n-4-6n+3$
=$2n^{2}-n^{2}-6n-n-6n+3-2-4$
=$(2n^{2}-n^{2})+(-6n-n-6n)+(3-2-4)$
=$n^{2}-13n-3$
=$(3)^{2}-13(3)-3$
=$9-39-3$
=$-30-3$
=$-33$
