1,填空题
化简：（-2xy^2)^2 X 3x^2y / (-x^3y^4)
=4x^2y^4*3x^2y/(-x^3y^4)
=12x^4y^5/(-x^3y^4)
=-12xy
2,先化简,再求值
3,(a+1)^2-(a+1)(2a-1).其中a=负根号3
(a+1)^2-(a+1)(2a-1)
=(a+1)[(a+1)-(2a-1)]
=(a+1)(2-a)
=-a²+a+2
当a=-√3时
原式=-(-√3)²-√3+2=-√3-1
4,分解因式 4xy^2-4x^2y-Y^3
4xy^2-4x^2y-y^3
=-y(4x^2-4xy+y^2)
=-y(2x-y)^2
5,如图,在三角形ABC中,