我自己是这样写的，不知道错在哪
a=thisform.text1.Value
b=thisform.text2.Value
c=thisform.text3.Value
IF a=0
IF b=0
IF c=0
thisform.text5.value=[全解]
ELSE
thisform.text5.value=[无解]
ENDIF
ELSE
thisform.text5.value=-(c/b)
ENDIF
ELSE
IF b^2-4*a*c<0
thisform.text5.value=[无解]
ELSE
thisform.text5.value=(-b+SQRT(b^2-4*a*c)) /(2*a)+ (-b-SQRT(b^2-4*a*c)) /(2*a)
thisform.Refresh