右图是a、b两种固体物质的溶解度曲线,下列说法中,正确的是()
A:20oC时,a物质的溶解度是5
B:在20℃时,a、b的饱和溶液中溶质的质量分数相同
C:a的溶解度随温度升高而增大,b的溶解度随温度升高而减小
D:将b的不饱和溶液变为饱和溶液,可以通过升温实现。
Today is Sunday. It's a sunny day. I'm in the park with my best friends Mary and Carol. There are many people in the park. They're doing different kinds of things. Some are walking by the lake. Some are talking under a big tree. Some are singing. Some are dancing on the playground. There are some kids playing tennis. Mary, Carol and I are sitting by the pool. It's really a fun day. The people here are all very happy. They're having a good time.
阅读短文,判断正误
若y=mxm2+m+1是一次函数,则m的值为( )
若圆O:x2+y2=4与圆C:x2+y2+4x﹣4y+4=0关于直线l对称,则直线l的方程是( )