(3/4)² + 0,8 * 3 1/8 = 3 1/16
1) 0,8 * 3 1/8 = 8/10 * 25/8 = 4/5 * 25/8 = 1/1 * 5/2 = 5/2
2) (3/4)² + 5/2 = 9/16 + 5/2 = 9/16 + 40/16 = 49/16 = 3 1/16