Question

3n+6m+(-15k)+(-n)+(-5m)+8k

Answer 1

3n+6m+(-15k)+(-n)+(-5m)+8k=3n+6m-15k-n-5m+8k=
=(3n-n)+(6m-5m)+(-15k+8k)=2n+m+(-7k)=m+2n-7k