Respuesta :

Answer:

See below.

Step-by-step explanation:

9: 1 * 5 *4 = 20

10: -1 * -1  * 2 * 7 = 14

11: (-6) * (3) = (-1 * 6) * 3 = -1 * -1 * -6 * 3 = -18

12: (-4) * (-8) = (-1 * 4) * (-1 * 8) = -1 * -1 * -4 * -8 = 32