Ineed getting the answer for the 1st question

Solve the word problem. the table shows the low outside temperatures for monday, tuesday, and wednesday. by how many degrees did the low temperature increase from monday to tuesday? this function table shows the outside temperature for a given a. 21.1⁰ b. 8.6⁰ c. 4.9⁰ d. 3.9⁰(the picture is the graph the the question is talking about.)

Someone answer this asap rn for ! a discount store’s prices are 25% lower than department store prices. the function c(x) = 0.75x can be used to determine the cost c, in dollars, of an item, where x is the department store price, in dollars. if the item has not sold in one month, the discount store takes an additional 20% off the discounted price and an additional $5 off the total purchase. the function d(y) = 0.80y - 5 can be used to find d, the cost, in dollars, of an item that has not been sold for a month, where y is the discount store price, in dollars. create a function d(c(x)) that represents the final price of an item when a costumer buys an item that has been in the discount store for a month. d(c(x)) =

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