looking at the picture above, hmmm we can see the graph touches at -5 and bounces right back up, that means even multiplicity, hmmm we can use say multiplicity of 2 for that, so hmm the graph also touches at 4 and bounces right back, same multiplicity.
so we can say, what's the equation of a function with roots at x = -5 and x = 4 and with multiplicity of 2 on each, that also passes through the point (0 , 80) ?
![\begin{cases} x = -5 &\implies x +5=0\\ x = -5 &\implies x +5=0\\ x = 4 &\implies x -4=0\\ x = 4 &\implies x -4=0 \end{cases}\hspace{5em}\boxed{\textit{each with multiplicity of 2}} \\\\[-0.35em] ~\dotfill\\\\ \stackrel{original~polynomial}{a ( x +5 )( x +5 )( x -4 )( x -4 ) = \stackrel{0}{y}} \hspace{5em}\textit{we also know that } \begin{cases} x=0\\ y=80 \end{cases}](https://img.qammunity.org/2024/formulas/mathematics/high-school/go2vxg56tsze4t5j35h2chcb1xyeuthm0n.png)

Check the picture below.