![](https://static.youtibao.com/asksite/comm/h5/images/m_q_title.png)
[单选题]
已知△ABC中,AB=17,AC=10,BC边上的高AH=8,则BC的长是()
A.21
B.15
C.6
D.21或9
![](https://static.youtibao.com/asksite/comm/h5/images/m_q_a.png)
D、21或9
![](https://static.youtibao.com/asksite/comm/h5/images/solist_ts.png)
A.21
B.15
C.6
D.21或9
D、21或9
A.若ABC=E,则A,B,C都可逆
B.若AB=AC,且A可逆,则B=C
C.若AB=AC,且A可逆,则BA=CA
D.若AB=O,且A≠O,则B=O
A.(AB)C
B.AC(B)
C.A(BC)
D.所有效率都相同
A.P(AB)=P(A)P(B)
B.P(BC)=P(B)P(C)
C.P(AC)=P(A)P(C)
D.P(ABC)=P(A)P(B)P(C)