I need help on this ,

Cherie measures and records the lengths and sizes of the same style of a sandal found at a shoe store. which equation can be used to determine the approximate shoe size, s, for a foot length of x inches? s = x – 2 s = 2x – 10 s = x + 6 s = 2x + 4

1foot = 12 inches; 1 yard = 3 feet

Whats the name of the vertical axis