The expression 120-15x represents how many invitations Luanne has to address after x days. The expression 120 + 15 (7-x) represents the number of invitations Darius has to address after x days. After how many days do Luanne and Darius have the same sumber of invitations to address?

not possible.

Step-by-step explanation:

number of invitations luanne has to address after x days = 120-15x

number of invitations Darius has to address after x days = 120 + 15 (7-x)

so, if the number of invitations should be the same for both of them,

we have to equate their number of invitations

120-15x = 120 + 15 (7-x)

subtracting 120 from both the sides,

-15x = 15 (7-x) = 105 - 15x

adding we 15x on both sides, we wont find any solution for x.

so, this isnt possible or the question must be wrong.