Let and be the roots of the quadratic equation 2x^2 - 8x + 7. Find 1/(2a) +1/(2b)

$\text{use the quadratic formula :} \\x = {-b \pm \sqrt{b^2-4ac} \over 2a}$

here is the roots:

http://www.cymath.com/answer.php?q=2x%5E2-8x%2B7%3D0

Don't use the quad. formula because i have a faster way.

In the quad. eq. ax²+bx+c=0

Sum of the 2 sol. = $-\frac{b}{a}$

Product of the 2 sol. = $\frac{c}{a}$

a and b are the 2 roots of the equation in your question.

Let's make it $\alpha$and$\beta$

$\frac{1}{2\alpha}+\frac{1}{2\beta}$

= $\frac{\alpha+\beta}{2\alpha\beta}$

=$\frac{-\frac{-8}{2}}{\frac{(2)(7)}{2}}$

= $\frac{4}{7}$