Answer
$$12x+12=72$$ or simplified
$$x+1=6$$
Work Step by Step
We can call our unknown number "$x$".
The product of a number and 12 can be written as $12x$ and if we add 12 to this we get $12x+12$.
So,
$12x+12=72$
IMPORTANT:
We could simplify this equation by dividing both sides by 12.
$\frac{12x}{12}+\frac{12}{12}=\frac{72}{12}$
This gives us,
$x+1=6$
