1. (a,b)+(3,1)=(6,7)
(a,b)=(6,7)−(3,1)(a,b)=(3,6)
Answer: a=3, b=6
2. (11,c)+(d,6)=(−12,−3)
(11+d,c+6)=(−12,−3)11+d=−12⇒d=−23c+6=−3⇒c=−9
Answer: c=−9, d=−23
3. (5,5)+(e,4)=(2,f)
(5,5)=(2,f)−(e,4)(5,5)=(2−e,f−4)5=2−e⇒e=−35=f−4⇒f=9
Answer: e=−3, f=9
4. (8,−3)−(5,g)=(h,2)
(3,−3−g)=(h,2)3=h−3−g=2⇒g=−5
Answer: h=3, g=−5