Troubleshooting Mathematica 5: How to Fix Common Issues with Solving Equations

[KenKEN Stone]

When i input "Solve[{ax + by == 0, cx + dy == 1}, {x, y}]", the machine answered "{{}}", the answer is not what i want, i want to know if my mathematica 5 has some problems.

 

[Johan de Vries]

Make sure you put a space between the factors like e.g. the "a" and the "x" in "a x". Otherwise Mathematica will see a variable "ax" which is not the same as "a" times "x"