—Yes, there is a flower shop on Jiefang Road.
A:how can I buy some flowers
B:where I can buy some flowers
C:how I can buy some flowers
D:where can I buy some flowers
已知在△ABC中,角A、B、C所对的边分别为a、b、c,b(b﹣3c)=(a﹣c)(a+c),且角B为钝角.
(1)求角A的大小;
(2)若a=12,求b﹣3c的取值范围.
下列物质中,不含有硅酸盐的是( )