Plz help. I have to show work too but I am confused

The tiles below are pieces of a normal ecg tracing representing a little less than two heartbeats at a resting rate of 80 bpm. arrange the tiles in their correct order. rank from first to last. do not overlap any tiles.

2y= 3 2 x−2 y = − 1 3 x + 1 y=− 3 1 x+1

Find the domain of the following expression: 1/(√x)-2