已知-3已知-3
已知-3Iy-2I-I3y-9I+Iy+3I=2-y-(9-3y)+y+3=3y-4
∵-3∴y-2<03y-9=3(y-3)<0y+3>0∴原式=2-y-9+3y+y+3=-4+3y (完整过程)不明白,可以追问,谢谢 祝学习进步! (望采纳)
3y-4