2. 7 * 4

(13 - 4) * 4 = 9 * 4 = 36

4 * (11 - 8) = 4 * 3 = 12

5 * 4 = 20

4 * 6 = 24

(17 - 9) * 4 = 8 * 4 = 32

(50 - 45) * 4 = 5 * 4 = 20