Which of the following best describes the expression 9(x + 7)?

the sum of constant factors 9 and x + 7

the product of constant factors 9 and x + 7

the product of a constant factor 9 and a 2-term factor x + 7

the sum of a constant factor 9 and a 2-term factor x + 7

best answer gets !

5is a constant. (it has no variables)
x + 2 is not a constant. it does, however, have two terms, x and 2. 
(terms are seperated by addition/subtraction)

this rules out a and b.

as for 5(x+2) implies  multiplication, which would be a product, not a sum.

d. the product of a constant factor 5 and a 2-term factor x+2