Make sure you are using the Quadratic Formula like this:
\(x = {-b \pm \sqrt{b^2-4ac} \over 2a}\)
and not as you wrote it in your question.......if you still get wrong answers , respond to this post....
for the first one a =1 b = 20 c = 51 (make sure your quadratic is in the form a x^2 + b x +c = 0 )
