You order the hardcover book shown from a website that offers free shipping on orders of $25 or more. Write and solve an inequality that represents how much more you must spend to get free shipping

If P = price of the hardcover book, then

We have to spend $25-P, if P = $25

Step-by-step explanation:

Lets call P the price of the hardcover book, in $. We can suppose that P is less than 25, otherwise we shoudnt spend on anything else to get the free shipping. If X is the amount that we have to spend to reach 25, then we get that P+X = 25. If P is known, we can obtain X by substracting P in both sides, therefore

X = 25-P

We conclude that if the price of the book P is less than 25, then we have to spend $25-P. Otherwise we have to spend 0.