Show that f is strictly monotonic on the given interval and therefore has an inverse function on that interval: f(x) = cot(x), (0,pi)

The price of an item has been reduced by 30%. the original price was $30. what is the price of the item now ?

Table which ratio is equivalent to 3: 7? 6: 7 3: 21 24: 56 15: 30

Me! i really need to get this right before 9. prove the divisibility of 7^6+7^5-7^4 by 11. use factoring so you get a number times 11. just tell me the number. i need this done asap