x1 = (-b[ +|-] Sqr(b ^ 2 - 4 * a * c)) / 2 * a的vb代码是多少!

代码Private Sub Command1_Click()Dim a,b,c,x1,x2a = InputBox("a",,2)b = InputBox("b",,4)c = InputBox("c",,1)If b ^ 2 - 4 * a * c < 0 ThenMsgBox "无解"Elsex1 = (-b + Sqr(b ^ 2 - 4 * a * c)) / (2 * a)x2 = (-b - Sqr(b ^ 2 - 4 * a * c)) / (2 * a)MsgBox "解得：" & x1 & "," & x2 & ""Print x1,x2End IfEnd Sub当 b ^ 2 - 4 * a * c < 0 方程无解,还有MsgBox "解得：" & x1 & "," & x2 & ""Print x1,x2这两句重复了,没必要 再问： MsgBox "解得：" & x1 & "，" & x2 & "" 这句是什么意思啊？？ 还有什么显示不出来啊？？