We are given a problem that can be solved using an inequality. We are told that Toni can carry a maximum of 17 lb. Therefore, the sum of the weights inside her backpack must be smaller or equal to 17 lb. The sum of the weight inside her backpack is 1 lb lunch, 2 lb clothes, and 2n books (n = number of books). We can write this mathematically like this:
![1+2+2n\le17](https://img.qammunity.org/2023/formulas/mathematics/college/kn9na8hvb703u8hwl6jroo0gzhq06a71i2.png)
Now we solve for "n", first by solving the operations, like this:
![3+2n\le17](https://img.qammunity.org/2023/formulas/mathematics/college/jpiy7kgjqmkwj3ljb7ujqmsb666mqzv3r2.png)
Now we subtract 3 on both sides of the inequality:
![\begin{gathered} 3-3+2n\le17-3 \\ 2n\le14 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/95bvp1og2rahwns7sw76bs0pz39tgajhc5.png)
Now we divide both sides by 2
![(2n)/(2)\le(14)/(2)](https://img.qammunity.org/2023/formulas/mathematics/college/pxq12i3xdx9kjslim0tomxgyd7hwttmp3n.png)
![n\le7](https://img.qammunity.org/2023/formulas/mathematics/college/w2eb1fzfp403gmx2fuhcyl0yernv22zqkt.png)
This means that Toni can carry at most 7 books