Question 84 (ii)
Simplify
(3x+2y)2−(3x−2y)2
We have, (3x+2y)2−(3x−2y)2 =[(3x+2y)+(3x−2y)][(3x+2y)−(3x−2y)] [using the identity, a2−b2=(a+b)(a−b)] =(3x+2y+3x−2y)(3x+2y−3x+2y)=6x×4y=(6×4)×xy=24xy
Question 84 (i)
(3x+2y)2+(3x−2y)2