Simplify the expression csc(-x)/1+tan^2x)

Write two subtraction equations that are equivalent to 5 + 12 = 17.

The cost of using a service is $0.25 per min. what equation correctly represents the total cost c, in dollars, for d days of use?

Suppose that in 2008 , 840,800 citizens died of a certain disease assuming the population of teh country is 399 miliion, what is the mortality rate in units of deaths per 100,000 people?