Question

6 less than the product of a number and 3 is -18..what is the number?

Answer 1

The product of a number and 3 can be represented as 3n (where n = unknown number). Then 6 less than 3n is 3n - 6. 

3n - 6 = -18
3n = -12
n = -4

Check: 
-4 x 3 = -12
-12 - 6 = -18 (this works!)