Respuesta :

The number of solutions of a quadratic equation

[tex]ax^2+bx+c=0[/tex]

Depends on its discriminant

[tex]\Delta = b^2-4ac[/tex]

  • If [tex]\Delta>0[/tex] there are two distinct solutions
  • If [tex]\Delta=0[/tex] there are two coincident solutions
  • If [tex]\Delta<0[/tex] there are no solutions.

We know that there are two real solutions (I assume you mean distinct solutions), so we know that the discriminant is positive:

[tex]b^2-4ac = 9+28t > 0 \iff t>-\dfrac{9}{28}[/tex]