2(a-2)(a+2) = 2(a^2 - 4) = 2a^2 - 8
x(x+4)(x-4) = x(x^2 - 16) = x^3 - 16x
5c(c+3)(c-3) = 5(c^2 - 9) = 5c^2 - 45
7d^2(d-1)(d+1) = 7d^2(d^2 - 1) = 7d^4 - 7d^2
2(a-2)(a+2) = 2(a^2 - 4) = 2a^2 - 8
x(x+4)(x-4) = x(x^2 - 16) = x^3 - 16x
5c(c+3)(c-3) = 5(c^2 - 9) = 5c^2 - 45
7d^2(d-1)(d+1) = 7d^2(d^2 - 1) = 7d^4 - 7d^2