Chapter 11.1, Problem 15PSB

To determine

To find : Restrictions on the value of x

Answer to Problem 15PSB

The restrictions are $1.3<x<3.1$

Explanation of Solution

Given information : The following information has been given

The area of the rectangle is between $84{\text{ mm}}^2$ and $124{\text{ mm}}^2$

Formula used : The area of any rectangle will be

  $A=(lengt{h}_1)(widt{h}_1)$

Calculation : We can find the area of the rectangle as

  $A=(8)(5x+4)=40x+32$

Now, we know that

  $84{\text{ mm}}^2<A<124{\text{ mm}}^2$

Thus, we can say that

  $84<40x+32<124$

Hence, we can say that

  $1.3<x<3.1$