1. 18 2 (18 ) 2.1 (1 ) 2.2 (2 ) 2.3 (2 ) 2.4 (4 ) 2.5 (4 ) 2.6 (5 ) 1. 2. 2. 19 2.1 1. 2. 2.1 1. x y 2. 2.1 3. -5 x -5 x -5 -5x0 x 1 x1 2.2 1. 2. 2.2 2.2 2.2 1. 1, 2 3 -3…
