We can find the quadratic polynomial if we know the sum of the roots and product of the roots by using the formula
$\mathrm{x}^{2}-($ sum of the zeroes $) \mathrm{x}+$ product of zeroes
$\Rightarrow \mathrm{x}^{2}-\left(-\frac{1}{2}\right) \mathrm{x}+(-3)$
$\Rightarrow x^{2}+\frac{1}{2} x-3$
Hence, the required polynomial is $x^{2}+\frac{1}{2} x-3$.