Same signs
When you multiply two positive or two negative numbers, the answer will be positive.
5 x 7 = 35
-5 x - 7 = 35
Different signs
When you multiply a positive and a negative number together, the answer will be negative.
5 x -7 = -35
-5 x 7 = -35
7 x -5 = -35
-7 x 5 = -35