At a race there were horses and jockeys. there were 82 feet and 26 heads. how many horses and how many jockeys were there?

One expression below in undefined, and the other expression has a well defined value. which expression is undefined and explain why it has no value. which expression is defined? what is the value of that expression and how do you know? what is a different expression using a trig inverse function that is also undefined?

The heaviest 16% of all men in weight weigh more than how many pounds ?

If f(x)=x^3 and g(x)=2x+7 when g(x)=-5