几道初一数学题,各位大哥大姐帮帮忙~1.若-2是m的立方根,则m²+m=_2.已知三次根号(y-1)与三次根号(1-2x)互为相反数,则x/y的值是_3.解方程组{x+y-z=11,y+z-x=5,z+x-y=1,则x=_,y=_,z=_4.若x=2y+3z=10,4x+3y+2z=15,则x+y+z的值为_ A.2 B.3 C.4 D.5
2019-06-02
几道初一数学题,各位大哥大姐帮帮忙~
1.若-2是m的立方根,则m²+m=_
2.已知三次根号(y-1)与三次根号(1-2x)互为相反数,则x/y的值是_
3.解方程组{x+y-z=11,y+z-x=5,z+x-y=1,则x=_,y=_,z=_
4.若x=2y+3z=10,4x+3y+2z=15,则x+y+z的值为_
A.2 B.3 C.4 D.5
优质解答
1.m=-8,m²+m=56
2.y-1=-(1-2x)
y-1=2x-1
y=2x
x/y=1/2
3.x+y-11=z,代入后面两式:
y+x+y-11-x=5,2y=16,y=8
x+y-11+x-y=1,2x=12,x=6
6+8-11=z,z=3
4.x=10
2y+3z=10,————(1)
40+3y+2z=15,3y+2z=-25—————(2)
由(1)(2)得:
2y=10-3z,y=5-3/2z
15-9/2z+2z=-25
-5/2z=-40
z=16
y=5-24=-19
X+y+z=10-19+16=7
1.m=-8,m²+m=56
2.y-1=-(1-2x)
y-1=2x-1
y=2x
x/y=1/2
3.x+y-11=z,代入后面两式:
y+x+y-11-x=5,2y=16,y=8
x+y-11+x-y=1,2x=12,x=6
6+8-11=z,z=3
4.x=10
2y+3z=10,————(1)
40+3y+2z=15,3y+2z=-25—————(2)
由(1)(2)得:
2y=10-3z,y=5-3/2z
15-9/2z+2z=-25
-5/2z=-40
z=16
y=5-24=-19
X+y+z=10-19+16=7