3/7x5/13-(9/14-3/14)x(-11/13)-3/7x3/13

3/7X5/13-(9/14-3/14)X(-11/13)-3/7X3/13 3/7x5/13-(9/14-3/14)x(-11/13)-3/7x3/13 x1-x2+x3=1x2-x3+x4=21若x1,x2,x3,x4,x5满足方程组 x3-x4+x5=3x4-x5+x1=4x5-x1+x2=5求x2 x3 x4的值2已知 x1+x4+x6+x7=39 x2+x4+x5+x7=49 x3+x5+x6+x7=41 x4+x7=13 x5+x7=14 x6+x7=9 x1+x2+x3+x4+x5+x6+x7=9求x7的值若x1,x2,x3,x4,x5满足方程组 x1-x 一道数学题：3/7x5/13-（9/14-3/14）x（-11/13）-3/7x3/13 (1+2+3+4+5+6+7+8+9+10+11+12+13+14+15)x5=? 3.4X5.3+5.9X4.7+2.5X5.3 1x5+2x5+3x5+4x5+5x5… 麻烦给我一个公式. 7(x-9-5-7)+0x9+1x5+2x7=y6(x-5-2-1)+15x1+14x2+13x5=y (9/5X10/7-3/1)X5/6 递等式计算：1/7+x5/7+3/8 解方程：6/7+3x=13/14 求线性方程组的全部解x1+x2-3x4-x5=2x1-x2+2x3-x4=14x1-2x2+6x3+3x4-4x5=82x1+4x2-2x3+4x4-7x5=9 (7分之3一14分之1)÷21分之5x5分之3过程 2/(3/4-1/6)x5/9 7/6x（1/4-1/3）x5/16x5/3 简便计算 1.5x5/8+7x5/8=?2.3/4x5/7-3/4x1/7=?3.7/8x3/17x5/7=?4.11/19x2/7x5/11没分给对不起啊、、 有2道分数简便运算奥数题不会.1/2X5+1/3X5+1/8X11+.+1/20X23=?2002/1x3+2002/3X5+2002/5X7+2002/7X9+2002/9X11=? 求方程组x1+3x2+x3+2x4+4x5=3 2x1-x2+8x3+7x4+2x5=9 4x1+5x2+6x3+11x4+10x5=15的全部解线性代数 用简便方法计算!2/7x5/9x（36x28） 7/9÷13/5+2/9x5/13（5/6-7/12x15/14）÷5/4 26/21-1/5-8/9÷10/9