changing the number in the f(x) will shift right and left ( + for left and - for right ) and changing out f(x) will shift up and down ( + for up and - for down)
So if there is 7 people and shakes the hand of everyone once it would be 6 shakes for one person to shake all the 7 people.6 because himself is counted as one. So if we multiply 6x7 we would have our answer which in this case is 42 42 handshakes in total from everybody.
