Final answer:
The linear equation representing the number of pages John has left after x days is y = 450 - 30x, where y is the number of pages left and x is the number of days.
Step-by-step explanation:
To write a linear equation to represent the number of pages John has left to read after x days, we need to determine the rate at which John is reading the book. Given that John reads 30 pages per day and the book has 450 pages, the rate at which he is reading is 30/450 = 1/15 page per day.
So, after x days, John would have read x/15 pages. To find the number of pages he has left to read, we subtract the number of pages he has read from the total number of pages in the book:
Pages left to read = Total pages - Pages read
Pages left to read = 450 - (x/15)