求计算a的三次方b-2a²b²+ab三次方,4x²y²-4x²yz+x²z²
问题描述：
求计算a的三次方b-2a²b²+ab三次方,4x²y²-4x²yz+x²z²
还有a的三次方+9ab²-6a²b
答
=ab(a²-2ab+b²)
=ab(a-b)²
=x²(4y²-4yz+z²)
=x²(2y-z)²
=a(a²-6ab+9)
=a(a-3)²