下列计算正确的是( )
A.2a+3b=5ab |
B. |
C.-2-=- |
D.4b-b=b |
下列各式运算(1)-(-a-b)=a-b; (2)5x-(2x-1)-x2=5x-2x-1+x2;
(3)3xy-(xy-y2)=3xy-xy+y2; (4)(a3+b3)-3(2a3-3b3)=a3+b3-6a3+9b3
其中去括号不正确的有
A.(1)(2) | B.(1)(2)(3) | C.(2)(3)(4) | D.(1)(2)(3)(4) |
下列计算正确的是( )
A.x2y—2 x2y=— x2y | B.2(a+2b)=2a+2b |
C.7ab—(-3ab)=10 | D.a3+a2=a5 |
试题篮
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