-3x =21
1/3x =6
-1/2x =-7

-3x = 21
Divide -3 from both sides and you get x = -7

1/3x = 6
Divide 1/3 from both sides and you get x = 18

-1/2x = -7
Divide -1/2 from both sides and you get x = 14 (you get a positive answer from 2 negatives)

Dividing 1/3 is just multiplying by 3, and dividing -1/2 is just multiplying by -2

Iam thinking the answer is a.) knew