Why is the equation not the equation of a line of best fit for the data set below?

height (in.)
arm span (in.)
42
41
45
43
52
55
48
49
49
49
53
52
59
60
45
44
44
45
60
57

Adoughnut shop charges $0.50 for each doughnut and $1 for a carryout box. shirley has $10 to spend. which inequality can be used to find d, the number of doughnuts she could have bought if she also wants them in one carryout box?