Quadratic Formula:
[tex]x = \frac{-b(+-) \sqrt{b ^2-4ac} }{2a} [/tex]
All you have to do is substitute the values of a,b and c
in which case if refer to the standard equation you'll have
Ax²+Bx+C=0
then the coefficient for x² will be a, the coefficient of x will be b and c will be the value the value of the constant.
for the sign, whether you'll have positive or negative, just follow the sign of the coefficients..
