Answer:
12(n-3)
Step-by-step explanation:
Let
n -----> the number
1) The algebraic expression of "the sum of a number and negative 3" is equal to subtract 3 from the number
n+(-3)=n-3
2) The algebraic expression of "the product of 12 and the sum of a number and negative 3" is equal to multiply by 12 the sum of a number and negative 3
so
12(n-3)