) (2x +1)2 + (x - 7)(x + 7) – 3x (x +4) =
b) 2 (x +6)2 - x (x + 4) – 2(x -1)2 =
c) ( x +2)2 - 2 (2x + ) (2x - ) =
d) (7x -2y)2 + x (3x +9y) =
e) (7x2 + 3y2) (7x2 - 3y2) =
f) (a +b) (a -b) (a2 + b2) (a4 +b4) =
g) (3x - 5)(3x + 5) – 2(3x + 5)2 =