n的5次方-6倍n的三次方+9n
问题描述：
n的5次方-6倍n的三次方+9n
答
n^5-6n^3+9n=n(n^2-3)^2
答
n^5-6n^3+9n
=n(n^4-6n^2+9)
=n(n^2-3)^2
答
用n^5表示n的5次方.
n^5-6n^3+9n (先提出公因子n)
=n(n^4-6n^2+9)
=n[(n^4-3n^2)-3(n^2-3)] (中括号两个式子中提出公因子n^2-3)
=n(n^2-3)*(n^2-3)
=n(n^2-3)^2
答
原式=n(n^4-6n^2+9)=n(n^2-3)^2