Let \(\alpha \) and \(\beta\) be the 2 roots of the equation ax2+bx+c
\(\alpha + \beta = -\frac{b}{a}\)
\(\alpha \beta = \frac{c}{a}\)
\(\frac{1}{2\alpha}+\frac{1}{2\beta}\)
=\(\frac{\alpha+\beta}{2\alpha\beta}\)
=\(\frac{-\frac{-8}{2}}{2(\frac{7}{2})}\)
=\(\frac{4}{7}\)
.