RosettaCodeData/Task/Runtime-evaluation-In-an-environment/Liberty-BASIC/runtime-evaluation-in-an-environment.basic

 expression$ = "x^2 - 7"
Print (EvaluateWithX(expression$, 5) - EvaluateWithX(expression$, 3))
End

Function EvaluateWithX(expression$, x)
    EvaluateWithX = Eval(expression$)
End Function