问题
选择题
下列式子中正确的是[ ]
A.(-x+3y)-(2x-5y)=-x-2y
B.1-2(x2-x+1)=-2x2+2x-1
C.(2x+y-z)-(5x+y-z)=-2x-4y-2z
D.2(x2-2xy+y2)-(x2-4xy+2y2)=x2+4y2
答案
答案:B
下列式子中正确的是[ ]
A.(-x+3y)-(2x-5y)=-x-2y
B.1-2(x2-x+1)=-2x2+2x-1
C.(2x+y-z)-(5x+y-z)=-2x-4y-2z
D.2(x2-2xy+y2)-(x2-4xy+2y2)=x2+4y2
答案:B