单项选择题
A.145 B.150 C.155 D.160 E.A、B、C、D都不正确
A.15.25% B.16.78% C.17.17% D.17.65% E.A、B、C、D均不正确
A.a+(b-c)=a+b+c B.a-(b-c)=a-b-c C.a-(-b-c)=a+b+c D.a-(b+c)=a-b+c