Question

因式分解 (x²-1)(x+3)(x+5)+16

Answer 1

(x²-1)(x+3)(x+5)+16=(x+1)(x+3)(x-1)(x+5)+16=(x^2+4x+3)(x^2+4x-5)+16

=(x^2+4x)^2-2(x^2+4x)+1=(x^2+4x-1)^2