已知1/2x3=1/2-1/3,1/3x4=1/3-1/4,.计算1/2x3+1/3x4+1/4x5+1/5x6.

1x1-2x2+3x3-4x4+5x5-6x6.-100x100+101x101 解方程组X2+X3+X4=1 X1+X2+X3=5 X3+X4+X5=-5 X4+X5+X1=-3 X5+X1+X2=2 求齐次线性方程组x1+2x2+x3+x4+x5=1 2x1+4x2+3x3+x4+x5=2 -x1-2x2+x3+3x4 (2X2)/1X3+(4X4)/(3X5)+(6X6)/(5X7)+...+(20X20)/(19X21)==? 1/1X2+1/2X3+1/3X4+1/4X5+1/5X6……1/2007X2008 1x2/1+2x3/1+3x4/1+4x5/1+5x6/1+6x7/1 1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+......1/2008x2009 1/1x2+1/2x3+1/3x4+1/4x5+1/5x6+1/6x7 求解一个方程急 X（1次方）+X2+X3=5 X2+X3+X4=1 X3+X4+X5=-5 X4+X5+X1=-3 X5 解一道方程组x1+x2+x3=5,x2+x3+x4=1,x3+x4+x5=-5,x4+x5+x1=-3,x5+x1+x2 已知数据X1,X2,X3,X4,X5的平均数是X拔,则一组新数据X1+1,X2+2,X3+3,X4+4,X5+5的平均数 1分解因式：2x4-x3-13x2-15=?2.分解因式：x5+x4+x3+x2+x+1=?3分解因式：x4-4x2+6