t平方减2t开中括号t平方减2开小括号t减3收小括号收中括号.
问题描述：
t平方减2t开中括号t平方减2开小括号t减3收小括号收中括号.
答
t^2 - 2t[t^2-2(t-3)]
=t^2 - 2t[t^2-2t+6)]
=t^2 - 2t^3+4t^2-12t
=5t^2 - 2t^3-12t
= -t(2t^2-5t +12)
= -t(2t^2+3t -8t +12)=-t[t(2t+3)-4(2t+3)]
= -t(2t+3)(t-4)