The quadratic equation with roots a and b is given by:
[tex]x^2-(a+b)x+ab=0[/tex]Here a=1/2 and b=-4.
So the equation is given by:
[tex]\begin{gathered} x^2-(\frac{1}{2}-4)x+(\frac{1}{2})(-4)=0 \\ x^2+\frac{7}{2}x-2=0 \\ 2x^2+7x-4=0 \end{gathered}[/tex]The quadratic equation is as shown above.