y(y+4)-y(y-3)-9y

分类: 作业答案 • 2022-01-21 10:29:22

问题描述：

y(y+4)-y(y-3)-9y
详细解答

答

y(y+4)-y(y-3)-9y
=y[y+4-(y-3)-9]
=y(y+4-y+3-9)
=y(-2)
=-2y