What is the slope of the line

Astandard american eskimo dog has a mean weight of 30 pounds with a standard deviation of 2 pounds. assuming the weights of standard eskimo dogs are normally distributed, what range of weights would 99.7% of the dogs have? approximately 26–34 pounds approximately 24–36 pounds approximately 28–32 pounds approximately 29–31 pounds

Type the correct answer in each box. use numerals instead of words. if necessary, use / for the fraction bar. consider the given table.

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?