1. Which mathematical expression is a perfect square trinomial?, A. 6×2 2013 5xy + y2, B. 6×2 +13x 2013 28, C. 16×2 201340x + 25, D. 4×2 + 20x + 25, 2. Which of the following DOES NOT belong to the group?, A. 1 4 x4 2013 1, B. x2 2013 0.0001y4, C. 6×2 +13x 2013 28, D. 4×2 + 20x + 25