Answer :
remember, -(-x)=x because the negatives cancel out
so
when p=-6 and q=7
p+(-q)-3
-6+(-7)-3
-6-7-3
-13-3
-16
so
when p=-6 and q=7
p+(-q)-3
-6+(-7)-3
-6-7-3
-13-3
-16