Answer
1. Remove the parentheses applying the Distributive Property.
2. Write the terms in order of their degrees.
3. Add/subtract like terms.
Result: $ -k^{3}+12k^{2}+8k-16$
Work Step by Step
First, remove the parentheses.
The first parentheses are simply removed,
and the second are removed by distributing the minus among its terms:
$=8k^{2}+k-1-k^{3}+4k^{2}+7k-15$
...Write the terms in order of their degrees
$=-k^{3}+8k^{2}+4k^{2}+k+7k-1-15$
... Add/subtract like terms
=$ -k^{3}+12k^{2}+8k-16$
