Is there a way or a trick of knowing whether a trinomial is not factorable or factorable

like this one" 8x^2+17x+35 I guessed it was not factorable but is there a trick to be certian?

Question

Is there a way or a trick of knowing whether a trinomial is not factorable or factorable

like this one" 8x^2+17x+35   I guessed it was not factorable but is there a trick to be certian?

hartnn · Answer

yes, 
if in ax^2+bx+c 

$\large {b^2-4ac}$  is a perfect square
then the trinomial is factorable.

waheguru · Answer

Thanks Buddy

agent0smith · Answer

Hmm i guess I never thought about like that @hartnn but it makes sense, since you could solve with the quadratic formula and get rational solutions.