Answer:
the missing side length is
![(2x+5)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/vkn6w5n37wzctga03zd4vxeam7uvvou0e0.png)
Explanation:
we know that the volume of the rectangular prism is equal to
![v=LWH](https://img.qammunity.org/2020/formulas/mathematics/middle-school/9wxi4wyh5v4hnzr4o8ld6thg5uzijwhqgr.png)
In this problem we have
![v=L(x+4)(x+2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/3bqlm5cps9etksjwhhbv2yb3nxs9w0n1v6.png)
![v=2x^3+17x^2+46x+40](https://img.qammunity.org/2020/formulas/mathematics/middle-school/kpwr7uxguzffzulvx7zjdl0ergdw14e70n.png)
using a graphing tool find the x-intercepts of the function
see the attached figure
The x-intercepts are
![x=-4, x=-2.5, x=-2](https://img.qammunity.org/2020/formulas/mathematics/middle-school/xkg1tti6daysopmeg9k9gdn4nhmnk2yue1.png)
so
![v=2(x+2.5)(x+4)(x+2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/chw3vaab4n8no42ehc2dt5cmcewwggatf0.png)
![v=(2x+5)(x+4)(x+2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/vykt29yibxwptn4y1vlw2pv8ni5n81ixm9.png)
therefore
the missing side length is
![(2x+5)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/vkn6w5n37wzctga03zd4vxeam7uvvou0e0.png)