Answer:
Read the explanation!
Step-by-step explanation:
Let the "certain number" be [tex]x[/tex].
([tex]*[/tex] is a symbol for multiplication).
Create a few equations and expressions:
The sum of 12 and a certain number: [tex]12 + x[/tex]
The product of 3 and the number: [tex]3 *x = 3x[/tex]
The sum of 12 and a certain number is equal to the product of 3 and the number:
[tex]12 + x[/tex] = [tex]3x[/tex]
Solve!
12=3x-x
12=2x
x=6
