[sealonlin]

Solve[{ax + y == 7, bx - y == 1}, {x, y}]是从mathematica官方网站弄得，为啥总是提示错误：General::ivar: 5+6 x is not a valid variable. >>，
输出是Solve[{5 + ax + 6 x == 7, -5 + bx - 6 x == 1}, {x, 5 + 6 x}]
试了其他简单的联立方程，也是这些提示