因式分解填空:ab²-4a=?,a³-4ab²=?,x²y-4y=?

问题描述:

因式分解填空:ab²-4a=?,a³-4ab²=?,x²y-4y=?

ab²-4a=a(b²-2²)=a(b+2)(b-2)
a³-4ab²=a[a²-﹙2b﹚²]=a﹙a+2b﹚﹙a-2b﹚,x²y-4y=y﹙x²-2²﹚=y﹙x+2﹚﹙x-2﹚

因式分解填空:ab²-4a=?,a³-4ab²=?,x²y-4y=?
ab²-4a=a(b²-4)=a(b+2)(b-2)
a³-4ab²=a(a²-4b²)=a(a+2b)(a-2b)
x²y-4y=y(x²-4)=y(x+2)(x-2)