Explain what the variable represents in an addition or subtraction expression

In the football stadium, there are 18 empty seats out of 360 total seats. (1a) write the ratio of empty seats to total seats as a fraction in simplest form. (1b) then explain its meaning.

Aline parallel to a triangle's side splits ab into lengths of x - 5 and x + 2. the other side, ac, is split into lengths of x and x + 12. what is the length of ac? a) 12 b) 24 c) 36 d)

Olga used 100 ounces of flour to make 225 muffins. how many ounces of flour will be used to make 300 muffins?