−6x+14<−28 AND3x+28≤25

I'm being volume of cylinder with 13 in. radius and 30 in height answer choices in pic

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?

Write numerical coefficient of y² in the expression 2x² - 15xy – 7y²