If (x2−y2)=18 and (x−y)=3, find the value of x2+y2+2xy.
27
81
243
729
(x2−y2)=(x−y)(x+y)=18
(x−y)=3 (x+y)=183=6
We know the following is an identity
(x2+y2+2xy)=(x+y)2 = 62=36
If (x2-y2) =18 and (x-y) =3, find the value of 16x2y2