The difference between a number x and 18 is 22?

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

According to a study conducted in 2015, 18% of shoppers said that they prefer to buy generic instead of name-brand products. suppose that in a recent sample of 1500 shoppers, 315 stated that they prefer to buy generic instead of name-brand products. at a 5% significance level, can you conclude that the proportion of all shoppers who currently prefer to buy generic instead of name-brand products is higher than .18? use both the p-value and the critical-value approaches.

Who long does it take to drive 150 miles at 45 miles per hour