I'm working my way through Mathematics for the Nonmathematician and in the section on quadratic equations the author introduces a method of solving them that involves creating a new equation where theroots are the rots of the old one, each increased by one-half the coefficient of x. One of the exercise equations is:

$\displaystyle 2x^2+8x+6=0$

but I don't know how to solve this due to the coefficient of $\displaystyle x^2$. Can anybody explain it to me?

EDIT:It's actually the pq formula that's used.