Let be a quadratic equation.
It is given that, coefficient of x2 and the constant term of a quadratic equation have opposite signs
⇒ ac < 0
⇒ 4ac < 0
⇒ −4ac > 0
⇒ b2 −4ac > 0
⇒ Discriminant > 0
⇒ Roots are real and distinct
Hence, If the coefficient of x2 and the constant term of a quadratic equation have opposite signs, then the roots of the quadratic equation are real and distinct.