How do i know this shape is not a regular polygon

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.

What is the value of x in the following equation. -x ^3/2 = -27

Vanessa earns a base salary of $400.00 every week with an additional5% commission on everything she sells. vanessa sold $1650.00 worth of items last week.