No output solving 3 equations in 3 variable using Solve[ ]?

Questions
,
1
Open in Wolfram Cloud ↗
2

Try:

   eq = Rationalize[{m1, m2, m3}, 0];
   Solve[eq, {x, y, z}]

  (*{{x -> -(2986243790645883105455758358098195118556533001223336622172815\
  95320218030787297467003699784937656128630985195404293779345/
      122509485374294293794510320145189527584750827993252931995775611287\
  31463104731917954143845606655037), 
    y -> 360193320714837502461108755235814898426025986503897780740376984\
  7336638393825822545137993153228989027658267755878411291/
     1225094853742942937945103201451895275847508279932529319957756112873\
  1463104731917954143845606655037, 
    z -> 243238456696344063017037725294492493070825115410091835761432292\
  011917023278886765613559961661062168696584881661936232099735/
     1225094853742942937945103201451895275847508279932529319957756112873\
  1463104731917954143845606655037}}*)

  % // N(*Numeric solution:*)
  (*{{x -> -2.43756*10^22, y -> 2.94013*10^20, z -> 1.98547*10^25}}*)

Solve is symbolic solver need exact values.

3

Is there any direct command to solve these equations? If someone does not use the rationalize command.

4

Also if I want to use the ans and want to find the value of “3x+2y”. It will simply show 3x+4y in output not calculate the numeric value of it

5

If your problem is linear then this

{vector,matrix}=CoefficientArrays[{m1,m2,m3},{x,y,z}];
solution=LinearSolve[matrix,vector]

will extract your coefficients from your equations and solve the linear system without needing to know or use Rationalize or N, and this then displays x,y,z

{2.43756*^22,-2.94013*^20,-1.98547*^25}

and then this will substitute that solution into your 3x+2y expression

ReplaceAll[3x+2y,Thread[Rule[{x,y,z},solution]]]

which displays the result

7.25388*^22

If you manually extract the coefficients from your equations and or insert the solution into your expression then you could do this without needing to know most of these functions.

6

Your equations are very poorly conditioned. The output can be meaningless:

{vector, matrix} = CoefficientArrays[{m1, m2, m3}, {x, y, z}];
matrix // Inverse
7

Solve in general handles numeric values as well.