下列计算正确的是( )
A.2x2•3x3=6x3 | B.2x2+3x3=5x5 |
C.﹣12a3b4÷2a3b2=﹣6b2 | D.![]() ![]() ![]() |
下列各式中,正确的是( )
A.2a+3b=5ab | B.-2xy-3xy=-xy |
C.-2(a-6)=-2a+6 | D.5a-7=-(7-5a) |