Question

A rectangular pen for a pet is 5 feet longer than it is wide. Give possible width of the pen if its area must be 204 and 750 square feet, inclusively.

Answer 1

Your question doesn't make any sense to me.

What do you mean by

its area must be 204 and 750 square feet, inclusively?

Answer 2

perimeter = 2(width+length)
length = width+5

a = w(w+5)

so, given the limits on the area,

204 <= w(w+5) <= 750

if w(w+5) >= 204,
w^2 + 5w - 204 >= 0
w>=12

if w(w+5) <= 750
w^2+5w-750 <= 0
w<=25

so, 12 <= w <= 25