Tried graphing this, but it looks like all of the last three are solutions...

Autility company burns coal to generate electricity. the cost c(p), (in dollars) of removing p percent of the some stack pollutants is given by c(p)= 85000p/100-p a) find the cost to remove 30% of the pollutant b) find where the function is undefined

These question are hard can you me with answers

Is it true that product of 3 consecutive natural numbers is always divisible by 6? justifyyour answer