Find the area of the bathroom/toilet

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?

Which is greater, 7 p 5 or 7 c 5? 7p5 7c5

Solve the system of equations using the linear combination method. {4x−3y=127x−3y=3 enter your answers in the boxes.