Question

if a-b=12and ab=8 then find the value of a2-b2

Answer 1

=(a-b)2=a2+b2-2ab
=(12)2=a2+b2-2×8
=144=a2+b2-16
=128=a2+b2
=(a+b)2=a2+b2+2ab
= (a+b)2=128+16
=a+b=
$\sqrt{144}$
=a+b=12
a2-b2=(a+b)(a-b)=12×12=144