Answer 1

public double QuadraticP(double[] Input) {
double a = 0, b = 0, c= 0;
for (int i = 0; i != 4; i++) {
switch (i) {
case 0:
a = Input[i];
break;
case 1:
b = Input[i];
break;
case 2:
c = Input[i];
break;
}
}
double x = ( (-b) + Math.Sqrt(Math.Pow(b, 2) - (4 * a * c) ) )/(2*a);
return x;
}

public double QuadraticN(double[] Input) {
double a = 0, b = 0, c = 0;
for (int i = 0; i != 4; i++)
{
switch (i)
{
case 0:
a = Input[i];
break;
case 1:
b = Input[i];
break;
case 2:
c = Input[i];
break;
}
}
double x = ((-b) - Math.Sqrt(Math.Pow(b, 2) - (4 * a * c))) / (2 * a);
return x;
}

There, as a function.
*Totally not copied and pasted from one of my projects*