ax2+bx+c=0 has roots of α and β
∴Roots=−2b±√4b2−4ac2a
∴Roots=−b±√b2−aca
∴α=−b+√b2−aca,β=−b−√b2−aca
Ax2+2bx+c=0 has roots α+δ,β+δ
Roots=−2B2√4B2−4AC2A
∴α+δ=−B+√B2−4ACA,β+δ=−B−√B2−4ACA
α−β=−b+√b2−ac+b+√b2−aca⇒α−β=2√b2−aca...(1)
(α−δ)−(β−δ)=−B+√B2−AC+B+√B2−ACA⇒α−β=2√B2−ACA...(2)
(1) = (2) [∵LHSareequal]
∴2√b2−aca=2√B2−ACA⇒√b2−acB2−ac=aA⇒b2−acB2−AC=(aA)2