how do u find the roots of the equation 2xsquared+7x-1=0
Or you can complete the square:
$\displaystyle 2x^2 + 7x - 1 = 0$
$\displaystyle 2x^2 + 7x = 1$
$\displaystyle 2 \left ( x^2 + \frac{7}{2} \right ) = 1$
$\displaystyle 2 \left ( x^2 + \frac{7}{2} + \frac{49}{4} \right ) = 1 + 2 \cdot \frac{49}{4} $
$\displaystyle 2 \left ( x + \frac{7}{2} \right ) ^2 = \frac{51}{2} $
$\displaystyle \left ( x + \frac{7}{2} \right ) ^2 = \frac{51}{4} $
$\displaystyle x + \frac{7}{2} = \pm \sqrt{\frac{51}{4}}$
$\displaystyle x = -\frac{7}{2} + \pm \frac{\sqrt{51}}{2}$
(If you want more details, just ask. )
-Dan