A chemical has been introduced into a colony of one million bacteria. The number of live bacteria is decreasing exponentially every minute. Which equation could model the number of live bacteria, b, in the colony n minutes after the chemical is introduced?
1) AD=-1,000,000n + 0.125
2) B b = 1,000,000(0.125)
3) cb = 1,000,000(1.25)
4) D 0 = 1,000,000 - 1250