Easy
(x - 3) (x + 3)
x^2 - 9
(x + 4) (x - 4)
x^2 - 16
(9x + 1) (x - 9)
9x^2 - 80x -9
(3x - 5)^2
9x^2 - 30x + 25
(x + 2) (x^2 + 3x + 5)
x^3 + 5x^2 + 11x + 10
(x + 6) (x + 7)
x^2 + 13x + 42
(2x + 5) (5x - 2)
10x^2 +19x -10
(3x2 + 7) 2
9x4 + 42x2 +49
(x + 1) (x + 2)
x^2 + 3x + 2
(6x - 2) (6x +2)
36x^2 - 4
(11x + 6) (11x - 6)
121x^2 - 36
(4x3 - y)2
16x6 - 8x3y + y2