(x²+4x)(x²+4x+8)+16怎样因式分解

let x²+4x=t =>t(t+8)+16=t^2+8t+16=(t+4)^2=(x²+4x+4)^2=[(x+2)^2]^2=(x+2)^4.ans

原式=(x²+4x)²+8(x²+4x)+16
={(x²+4x)²+4}²