Answer:
a. -6
b. +6
c. -6
Step-by-step explanation:
minus times plus times plus = -
minus times minus times plus = +
minus times minus times minus = -
1 times 2 times 3 = 6
so:
-1 times 2 times 3 = -6
-1 times -2 times 3 = +6
-1 times -2 times -3 = -6