Originally Posted by

**kenny1999** yes, thank all for the answer

but I want to know.....

Usually by using the general cross method to factorize a quadratic polynomials x^2+bx+c, we will either be able to get (x-p)(x-q) where

p and q are integral values, or unable to factorize. But whether it can be factorized is highly determined by trial-and-error in cross method.

My question is (was) , is there any other way, rather than trial and error in the cross-method to determine whether

ax^2 + bx + c can be factorized into the form of (x-p)(x-q), where p and q are INTEGERS

I understand delta, if delta is less than 0, then the surd will be undefined in real region, so there is no value of x

and I also understand that if delta = 0 or bigger than 0 there will be real value of x, but my question is how to know if the roots of a

quadratic equation is an integer or not (not integers). Thanks all in advance