數學-因式分解

You must know these formula:
(x+y)²
=x²+2xy+y²
And
a²+2ab+b²
=(a+b)²

In this question:
(x²)(y²)+(z²)+2xyz
=x²y²+z²+2xyz
=x²y²+2xyz+z²
Get back in place
=(xy+z)²

x^2y^2= (xy)^2 (a^2)
2xyz (2ab)
z^2 (b^2)

因為 a^2+2ab+b^2=(a+b)^2

所以

(x^2)(y^2)+(z^2)+2xyz

= (xy)^2+2xyz+z^2
=(xy+z)^2

x²y² + z² + 2xyz
= (xy)² + 2(xy)(z) + z²
= (xy+z)² 【因為 (a+b)² = a² + 2ab + b²】

希望幫倒你！^^