1)(4b+1)(1-4b) = 1 - 16b^2
2)(a+3c)^2+(b+3c)(b-3c) = a^2 + 6ac + 9c^2 + b^2 - 9c^2 = a^2 + 6ac + b^2
3)(x+3)^2-(x-3)^2 = (x+3-x+3)(x+3+x-3) = 12x
4)(x-4y)^2+(x+4y)^2 = x^2 - 8yx + 16y^2 + x^2 + 8yx + 16y^2 = 2x^2 + 32y^2
5)(x-3)(x+3)-(x+8)(x-8) = x^2 - 9 - x^2 + 64 = 55
6)(p+1)^2-(p+2)^2 = (p+1-p-2)(p+1+p-2) = 1-2p
7)(y-2)(y-3)-(y-1)^2 = y^2 - 5y + 6 - y^2 + 2y -1 = -3y + 5
8)3x(3x+7)-(3x+1)^2 = 9x^2 + 21x - 9x^2 - 6x - 1 = 15x - 1
9)5b^2-(a-2b)^2 = 5b^2 - a^2 + 4ab - 4b^2 = b^2 + 4ab - a^2