P=x2−36x2−49=(x+6)(x−6)(x+7)(x−7)
Q=x+6x+7
Then , PQ=(x+6)(x−6)(x+7)(x−7)x+6x+7
PQ=(x+6)(x−6)(x+7)(x−7)×x+7x+6=x−6x−7
If (x+a) is a factor of x2+px+q and x2+mx+n, then the value of a is