若a>0,b<0时,化简|6-5b|+|8b-1|-|3a-2b|的结果是( ) A.3a+b+5 B.3a-11b+7 C.-3a+5b+5 D.-3a-11b+7
问题描述:
若a>0,b<0时,化简|6-5b|+|8b-1|-|3a-2b|的结果是( )
A. 3a+b+5
B. 3a-11b+7
C. -3a+5b+5
D. -3a-11b+7
答
∵a>0,b<0,
∴6-5b>0,8b-1<0,3a-2b>0.
∴|6-5b|+|8b-1|-|3a-2b|=6-5b-(8b-1)-(3a-2b)=6-5b-8b+1-3a+2b=-3a-11b+7.
故选D