What have you tried so far?
"Prove that..." is your responsibility, and while many of us (myself included) are willing and able to help, you have to show some effort besides registering for a forum and copying the question down in LaTex markup.
Ok, seeing the hypothesis i said: there are roots of the equation because its equivalent to . I set d and e in the given relation. and then i get stuck.
You're almost there. What is the discriminant of this quadratic? If you subtract 4ac from the given inequality, you will conclude that
("the discriminant") >= 0
and this implies that the quadratic has >= 1 real root.