In this equation, what is n?

n+6=20

variable or standard number

Can someone me with my hwplz(only the circled ones)

In each bouquet of flowers, there are 2 roses and 3 white carnations. complete the table to find how many roses and carnations there are in 2 bouquets of flowers.

Which letters from the table represent like terms? a and b b and c a and d b and d