方程2(x +1)=4x-8的解是()
A.![]() |
B.-3 | C.5 | D.-5 |
.已知多项式A=x2+2y2-z2,B=-4x2+3y2+2z2,且A+B+C=0,则C为()
A.5x2-y2-z2 | B.3x2-5y2-z2 | C.3x2-y2-3z2 | D.3x2-5y2+z2 |
下列各式中,去括号正确的是( )
A.x2-(2y-x+z)= x2-2y2-x+z | B.3a-[6a-(4a-1)]=3a-6a-4a+1 |
C.2a+(-6x+4y-2)=2a-6x+4y-2 | D.-(2 x2-y)+(z-1)=-2 x2-y-z-1 |
下列各组中的两项属于同类项的是( )
A.![]() ![]() |
B.-8a2b与5a2c; | C.![]() ![]() |
D.19abc与-28ab |
若-4x2y和-23xmyn是同类项,则m,n的值分别是( )k.Com]
A.m=2,n=1 | B.m=2,n=0 | C.m=4,n=1 | D.m=4,n=0 |