$\mathrm{f}\left(\mathrm{u}\right)=5{\mathrm{u}}^2+10\mathrm{u}$
\mathrm{f}(\mathrm{u})=5 \mathrm{u}^{2}+10 \mathrm{u}

It can be written as $5 \mathrm{u}(\mathrm{u}+2)$

$\therefore \mathrm{f}\left(\mathrm{u}\right)=0\Rightarrow 5\mathrm{u}=0\text{ or }\mathrm{u}+2=0$
\therefore \mathrm{f}(\mathrm{u})=0 \Rightarrow 5 \mathrm{u}=0 \text { or } \mathrm{u}+2=0
$\Rightarrow \mathrm{u}=0\text{ or }u=–2$
\Rightarrow \mathrm{u}=0 \text { or } u=-2

So, the zeroes of $f(u)$ are $-2$ and 0 .

Sum of the zeroes $=-2+0=-2=\frac{-2 \times 5}{1 \times 5}=\frac{-10}{5}=\frac{-(\text { coefficient of } x)}{\left.\text { (coefficient of } u^{2}\right)}$

Product of zeroes $=-2 \times 0=0=\frac{0 \times 5}{1 \times 5}=\frac{-0}{5}=\frac{\text { constant term }}{\left(\text { coefficient of } u^{2}\right)}$