(9x + 4) (9x - 4)
81x^2 - 16
(x+3)(x+5)
3m (2n -3x + 5k)
(5x+1)(2x+1)
(y - 4) (y^2 + 4y + 16)
y^3 - 64
(6m + 8w) (3x-7y)
6mn - 9 mx + 15 mk
10x^2 + 7x +1
18mx + 24xw - 42my - 56wy
x^2+8x+15