题目下列等式从左到右的变形,属于因式分解的是（ ）A.x2−4y2=(x+y)(x−4y)x^{2}-4y^{2}=\left(x+y\right)\left(x-4y\right)x2−4y2=(x+y)(x−4y)B.(x+4)(x−4)=x2−16(x+4)\left(x-4\right)=x^{2}-16(x+4)(x−4)=x2−16C.x2−2x+1=(x−1)2x^{2}-2x+1=\left(x-1\right)^{2}x2−2x+1=(x−1)2D.x2−8x+9=(x−4)2−7x^{2}-8x+9=\left(x-4\right)^{2}-7x2−8x+9=(x−4)2−7知识点：十字相乘法章节：数与式 / 因式分解
