How do I match multiple arguments?

You can pattern match all described cases like this:

def func(a: Int, b: Int, c: Double) = (a, b, c) match {
    case (a, b, 0) => b - a
    case (a, b, c) if c > 9 || a == b => 0
    case _ => 1 // add your logic here
}

Following on from my comments to Easy Angel's answer, I still feel this

if (c == 0)
   b -a
else if (c > 9)
   0
else if (a == b)
   0
else 
   1 // your logic here

is clearer. Basically because there isn't really any pattern to match here.