If α,β be the roots of x2+px+q=0 and α+h, β+h are the roots of x2+rx+s=0, then
pr=qs
α+β=−p, αβ=qα+β+2h=−r,(α+h)(β+h)=s
−p+2h=−r⇒h=p−r2 ........(i)
Now, αβ+h(α+β)+h2=s⇒q+h(−p)+h2=s⇒q+(p−r2)(−p)+(p−r2)2=s⇒q+(−p2+pr)2+p2+r2−2pr4=s
⇒4q−2p2+2pr+p2+r2−2pr=4s⇒4q−p2+r2−4s=0⇒r2−4s=p2−4q