已知﹣5.2xm+1y3与﹣100x4yn+1是同类项,求:mn+nm
解:∵﹣5.2xm+1y3与﹣100x4yn+1是同类项,
∴m+1=4,n+1=3,
∴m=3,n=2,
∴mn+nm=9+8=17.
—Yes. She always _____ her toys after playing with them.
已知a=0.42,b=30.4,c=log40.3,则( )
计算:(﹣3)×13=____.
如图所示,在磁铁正上方用弹簧挂着一条形磁铁,开关闭合后,当滑片P从a端向b端滑动过程中,则电流表的示数____ ,弹簧的长度将____ (选填变小、不变或变大).