(1)ax2+bx+c=0 的合法表达式: a * x ^ 2 + b * x + c = 0
(2)定义常量pi=3.14 的VB表达式: Const pi = 3.14
(3)mid("ABCDEFG ",4,2) 的结果是: "DE"
(4)right("ABCDEFG",4) 的结果是: "DEFG"
(5)len("北京奥运2008Beijing")的结果是:15
(6)33+val("256")的值是: 289
a*x^2+b*x+c=0
const pi as double =3.14
DE
DEFG
15
289