Quadratic formula = ( -b +/- square root of b^2-4ac ) / 2a
In this case, a=2, b= -7 and c= -3
So:
(7 +/- square root of (-7)^2 - 4*2*(-3) ) / 2*2
= (7 +/- square root of 49 + 24 ) / 4
= 7 +/- square root of 73 / 4
Using a calculator, you end up with the answers: 3.886 and -0.386