Answer:
(n+3)/7
Step-by-step explanation:
Let
n -----> the unknown number
we know that
The algebraic expression of the phrase " the sum of a number and three" is equal to
(n+3) -----> number n plus number 3
so
The algebraic expression of the phrase " the sum of a number and three divided by seven" is equal to
(n+3)/7 ----> divide (n+3) by the number 7
therefore
The expression is
(n+3)/7
