Why do you subtract 72 from 250 to find X?

If the perimeter of the garden is 37 ft. the width is x and the length is 15 ft. what is the width of the garden in feet?

How do i simply this radical expression?

In 1995 america online had about 3000000 users over the next decade users are expected to increase from a few million to the tens of millions suppose the number of users increased by 150% by the year 2000 how many users will there be in the year 2000