Does the relationship represent a function?

Write a corresponding real world problem to represent 2x - 125=400

Aswim teacher sells lesson packages. the best deal has the highest ratio of lessons to total cost.swim lesson packagesnumber of lessons total cost$10$4010 1 $8015$80which package is the best deal? l lesson for $105 lessons for $4010 lessons for $8015 lessons for $80mark this and returnsave and exit

What is the frequency of the sinusoidal graph?