Here's the question you clicked on:
Steeben
x^2+4x+13 complete the square and solve
Ok, first, is there any number that adds to the middle and multiplies to get the 3rd number?
IF not, move on to complex trinomials.
If that doesn't work out, continue on to use the quadratic formula.
If you need it, here is the formatted quadratic formula: http://www.purplemath.com/modules/quadform.htm