c)(x-3)(x+2)^2 - (x-3) = (x-3)(x^2 + 4x + 4 - 1) =
(x-3)(x^2 + 4x + 3) = (x-3)(x+1)(x+3)
d)(x-4)(2x+1)^2 - (x-4) = (x-4)(4x^2 + 4x + 1 - 1) =
(x-4)(x^2 + 4x) = x(x-4)(x+4)
e)(x+7)^2 - 5^2 = (x+7-5)(x+7+5) = (x+2)(x+12)
f)(x-5)^2 - 6^2 = (x-5-6)(x-5+6) = (x-11)(x+1)
g)(x-6-3x)(x-6+3x) = (-2x-6)(4x+6) = -4(x+3)(2x+3)
h)(x+2-4x)(x+2+4x) = (-3x+2)(5x+2)