# Chapter 9 - Quadratic Functions and Equations - 9-4 Factoring to Solve Quadratic Equations - Practice and Problem-Solving Exercises - Page 558: 34

8 feet

#### Work Step by Step

$(2x+8)(2x+6)=48+72$ $4x^2+12x+16x+48 = 120$ $4x^2+28x+48=120$ $(4x^2+28x+48)/4=120/4$ $x^2+7x+12 =30$ $x^2+7x+12-30 =30-30$ $x^2+7x-18=0$ $(x+9)(x-2)=0$ $x+9=0$ $x+9-9=0-9$ $x = -9$ (we can't have a negative length, so this is not an applicable answer) $x-2=0$ $x-2+2=0+2$ $x = 2$ This means the cement border should be 2 feet around all sides of the pool. $6+2=8$ $8+2 =10$

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.