In a linear equation the variable is the base and the is 1

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.

17 in long 1.3 ft wide and 8in high what is the volume

1) prove that 731^3−631^3 is divisible by 100 2) prove that 99^3−74^3 is divisible by 25