Irene R. answered 03/27/20
Senior Mechanical Engineer with 13+ years of Teaching Experience
Let's use the variable x to represent the unknown number.
Then we can write "the product of three and a number" as: 3x
Then "is eighteen" can be written as: = 18
Combining these gives us the following equation: 3x = 18
Solve using inverse operations:
3x = 18
3x/ 3 = 18/ 3
x = 6
The unknown number is 6