Question 125586
First of all, you need to find what your A,B,and C values are. 
{{{ax^2+bx+c=0}}}
{{{2x^2-13x-7=0}}}
a=2, b=-13, c=-7

Quadratic formula:
{{{x=(-b+-sqrt(b^2-4*a*c))/(2*a)}}}

Plug in your a,b,c values and solve.
{{{x=(-(-13)+-sqrt((-13)^2-4*(2)*(-7)))/(2*(2))}}}
{{{x=(13+-sqrt((-13)^2-4*(2)*(-7)))/(2*(2))}}}
{{{x=(13+-sqrt(169-4*(2)*(-7)))/(2*(2))}}}
{{{x=(13+-sqrt(169-8*(-7)))/(2*(2))}}}
{{{x=(13+-sqrt(169+56))/(2*(2))}}}
{{{x=(13+-sqrt(225))/(2*(2))}}}
{{{x=(13+-sqrt(225))/(4))}}}
{{{x=(13+- 15)/(4))}}}
{{{x=(13+ 15)/(4))}}}    ............            {{{x=(13- 15)/(4))}}}
{{{x=(28)/(4))}}}       ............             {{{x=(-2)/(4))}}}
{{{x=7}}}               ............       {{{x=-1/2}}}