7.下列运用等式的性质进行变形,正确的是( )
0 297906 297914 297920 297924 297930 297932 297936 297942 297944 297950 297956 297960 297962 297966 297972 297974 297980 297984 297986 297990 297992 297996 297998 298000 298001 298002 298004 298005 298006 298008 298010 298014 298016 298020 298022 298026 298032 298034 298040 298044 298046 298050 298056 298062 298064 298070 298074 298076 298082 298086 298092 298100 366461
| A. | 如果a=b,那么a+c=b-c | B. | 如果ac=bc,那么a=b | ||
| C. | 如果a=b,那么a(c2+1)=b(c2+1) | D. | 如果ab=3b,那么a=3 |