4x+3 x7/10=13/2

4x+3 x7/10=13/2 (10+x)x7/2-(10-x)x7/2=28如何解方程 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 （x-10）x7/8=56 x除（1+3/5）=13/4 要计算过程 解方程：5x-3x7/10=5/7 4x-3X7=29这个方程怎么解 3/2x(2.25+25/6)x7.7％]-15/13=? 3/2x(2.25+25/6)x7.7％]-15/13=? 解方程x+2 x7=28 Min Z= X1 +X2 +X3 +X4 +X5 +X6 +X7 +X8S.T.2X1 +X2 +X3 +X4 =1002X2 +X3 + 3X5 +2X6 + X7 =100X1 + X3 + 3X4 +2X6 +3X7 +4X8 =100X1,X2,X3,X4,X5 ,X6,X7,X8 >=0经过计算的最优解是X*= (40 ,20,0,0,0 ,30 ,0 ,0)T Z* =90但该解也是最优解X*= (10 ,50,0 帮我用lingo或者lindo算个题呗?x1+x4+x5+x6+x7>20x1+x2+x5+x6+x7>13x1+x2+x3+x6+x7>10x1+x2+x3+x4+x7>12x1+x2+x3+x4+x5+>16x2+x3+x4+x5+x6+>18x3+x4+x5+x6+x7>20格式不对也改下哈,>在lingo中应该和>=一样吧?min=(5x1+4x2+3x3+3x4+3x5+3x6+4x7) 7(x一3.6)=5.6 (x+2.8)÷2.5=10 3(x一2.7)=12 4x7十7(x一3.6)=5.6 (x+2.8)÷2.5=10 3(x一2.7)=12 4x7十3x=88 (50一2x)÷2=12 x2+3x+1=0求x7+1/x7的值 x2+3x+1=0,求x3+1/x3与x7+1/x7的值. 4X+8.60x2=30 4X-X=39 7X+90x7=1463 3X-2+X=50 X=多少 (是小题,格式, 2X/1x3+2X/3x5+2X/5x7+2x/7x9+2x/9x11=10 x=? lim[1/(1x4)+1/(4x7)+1/(7x10)+...+1/(3n-2)x(3n+1)]=_____ sn=1/1x3+4/3x5+9/5x7+```````+n2/(2n-1)x(2n+1)