[tex]\bf f(x) = 4(x + 7)^2(x - 7)^3\implies 0 = 4(x + 7)^2(x - 7)^3
\\\\\\
0=(x+7)^2(x-7)^3\implies
\begin{cases}
0=(x+7)^7\\
\qquad 0=(x+7)(x+7)\\
\qquad -7=x\\
\qquad -7=x\\
----------\\
0=(x-7)^3\\
\qquad 0=(x-7)(x-7)(x-7)\\
\qquad 7=x\\
\qquad 7=x\\
\qquad 7=x
\end{cases}[/tex]
the -7 is found there twice, so it has a multiplicity of 2
the +7 is there thrice, so it has multiplicity of 3
