下列的功能是输入一元二次方程ax2+bx+c=0(a≠0)的3个系数a、b、c,并判断它的根的情况,请将下列程序补充完整。 Dim a As Single,b As Single,c As Single Dim delta As Single a = Val(txtA.Text): b = Val(txtB.Text): c = Val(txtC.Text) delta =【1】 If delta > 0 Then lb1Result.Caption = ′′有两个不相等的′′ ElseIf delta = 0 Then lb1Result.Caption = ′′有两个相等的′′ 【2】 lb1Result.Caption = ′′没有′′ End If