—What's your idea about family education?— kids learn to be independent, it is for their future.
A:The earlier,the better
B:The more,the more
C:The earlier,the earlier
D:The better,the earlier
如图,PA为⊙O的切线,A为切点,⊙O的割线PBC过点O与⊙O分别交于B、C,PA=8cm,PB=4cm,求⊙O的半径.
已知ax=5,ax+y=30,求ax+ay的值.