вот я даже нашел))
в этой весчи я разберался неплохо, хотя не знал как применять))
String s;
Double a, b, c, x, f = 0;
Console.Write("Enter a ");
s = Console.ReadLine();
a = Convert.ToDouble(s);
Console.Write("Enter b ");
s = Console.ReadLine();
b = Convert.ToDouble(s);
Console.Write("Enter c ");
s = Console.ReadLine();
c = Convert.ToDouble(s);
Console.Write("Enter x ");
s = Console.ReadLine();
x = Convert.ToDouble(s);
if (4 != 0 && b != 0) //12
if (c + b / 4 != 0 && x - 4 / b != 0)//11
if (x / c + b / 4 > a / x - 4 /

//3
if (a - b != 0 && c != 0)//2
if (x + 7 / a - b != 0 && a + b / c != 0)//1
f = (x - 5 / x + 7 / a - b + b / a + b / c);
else
Console.WriteLine("");//1
else
Console.WriteLine("");//2
else //3
if (7 != 0 && c != 0)//10
if (x + a / 7 != 0 && a - b / c != 0)//9
if (x / x + a / 7 > a / a - b / c)//6
if (c != 0 && 4 != 0 && 6 != 0)//5
if (a - b / c != 0 && 7 / 4 - a / 6 != 0)//4
f = (x - 7 / a / a - b / c + c - c / b / 7 / 4 - a / 6);
else
Console.WriteLine("");//4
else
Console.WriteLine("");//5
else //6
if (b != 0)//8
if (a - 7 / b != 0 && a - c / b != 0)//7
f = (x - 7 / a - 7 / b * 6 / c - 5 / a - c /

;
else
Console.WriteLine("");//7
else
Console.WriteLine("");//8
else
Console.WriteLine("");//9
else
Console.WriteLine("");//10
else
Console.WriteLine("");//11
else
Console.WriteLine("");//12
Console.Write("f= ");
Console.WriteLine(f.ToString());
Console.WriteLine("... ");
Console.ReadKey();