The general solution for the quadratic equation ax^2 + bx + c = 0 is:
x = (-b +- sqrt(b^2 - 4ac) ) / 2a
NOTE: there are two solutions - one with a +sqrt( ) term and the other
with a -sqrt( ) term, so you will need two columns for the solutions.
If you have values for a in column A, values for b in column B and
values for C in Column C then you can just substitute the appropriate
cell references into the formula above in column D and column E, as
follows:
D1: = (-B1 + SQRT(B1^2 - 4*A1*C1) ) / (2*A1)
E1: = (-B1 - SQRT(B1^2 - 4*A1*C1) ) / (2*A1)
assuming your values start on row 1. Then just copy these two formulae
down the columns for as many values as you have in columns A to C.
Hope this helps.
Pete