When the factors of a trinomial are (x-p) and (x+q) then the constant teen of the trinomial is

(x-p)(x-q)

y(x-q) let y = x-p

yx - yq ... distribute

x(y) - q(y)

x(x-p) - q(x-p) ... replace y with x-p

x^2 - px - qx + pq distribute

x^2 + (-p-q)x + pq

The last expression is in the form ax^2+bx+c with a = 1, b = -p-q and c = pq

The constant term is the term without any variable x attached to it (either x or x^2), so the constant term is pq

sorry, i can't understand your question. will later if you describe more clearly!

: )