Question 36031
First, you need to know what the discriminant is.
It is the portion underneath the root in the quadratic formula.
{{{x = (-b +- highlight(sqrt( b^2-4*a*c )))/(2*a) }}} 
so now using the equation you have ...
{{{ x^2 + 6x - 7 = 0 }}}
{{{ b^2 - 4*a*c }}}
Plug in the values
{{{ 6^2 - 4*1*(-7) }}}
{{{ 36 - 4*1*(-7) }}}
{{{ 36 + 28 }}}
{{{ 64 }}}
because this number is positive, there are 2 roots.
if the number were 0, there would be one root.
if the number was negative, there are no roots.