X = number.
3X
===
The sum of four and the product of three and a number xxxx.
A single number cannot produce a product.
"The sum of a number and three times another number is 18. find the numbers if their product is a maximum?"
5290
A cube is a product in which a number is a factor three times. An example: 3 x 3 x 3 = 27
15
-1
999
108.
999
its 567
992