____×5 <30 6 ×____<25 4×____< 21
5×____<16 ____÷4 <5 3×____ < 20
如果x=2y=-1是方程组ax+by=0bx-cy=1的解,那么,下列各式中成立的是( )
—Come on, Sandy. Everybody will be lucky or ____(成功的) sometime in their life.
—Thanks, I'll try again.