To solve first we isolate are variables so we distubte to get -2y-2+21=3y then we add 2y to the opposite side to get -2+21=5y. Then we add -2+21 to get 19 so are equation is 19=5y. Next we just divide 19 by 5 to get y=(19/5) or option A
The smallest angle would be angle C. The reason why is because angle C is opposite of the shortest side (AB). The smallest angle in a traingle is opposite of the shortest side.